EDIT: To avoid my tone and ensure you get the impression this are my thoughts, I insert some "I thinks".
Guys, who cares how many skill trees the Inquisitor has exacty. We know we will have those 4 basic skill trees depending on the class, and then the specialization tree.
Maybe the "mark" skill is a new one and fits it in its own tree, or maybe that tree at level 7 (or whatever) becomes the specialization tree, or whatever, it doesnt matter. In any case, it is a good thing and an improvement of what we had so far. Now our Inquisitor I thinkwill be at least a little different from the companions, maybe we have another skill related, or maybe some passives, we will see.
In a gamescom gameplay video the devs said it banishes demons.
I really hope the guy there is playing in easy mode: there is no tactical depth in what he's doing (not to say he's pushing buttons randomly) and yet he seems to be advancing through the area without a problem...
It takes time to kill the demons and undead, but the party takes little damage. I guess the difficulty of the game now is not a matter of burst combat encounters, but more a war of attrition, meaning that in any given sidequest (like the Avvar one), you must defeat the boss without going through all your consumables. If you start losing too much health in those early encounters, maybe you have to go back to Skyhold or a camp, replenish consumables, and try again.
This is somewhat refreshing, since I always play hard/nightmare, and difficult encounters are those were you wipe in a matter of seconds due to an unattended mage/rogue, or are overrun fast. With this new philosophy, maybe an encounter were you lose 50% of the health of a couple of party members can be considered a failure, since you are using resources you will need in the incoming boss battle.
Im curious about it, and I will not be able to decide if I like it or not, until I try it. (It depends on how it is implemented)
But I am really interested and looking forward to it! 
I definitely think we'll see a few, if nothing else in the Necromancer tree. But we'll see few around I'm pretty sure. I just hope Necromancer tree also has a animate dead spell as well. I'll honestly be a little bummed if 'Necromancer' is just copy/paste entropy and that's that. I'll still end up getting it on my planned necro char but gonna be a little bummed if thats 'all' it is.
Stop saying things like "seeing a few in the Necromancer tree". This is not confirmed, but everything we have seen so far indicates that the Necromancer tree will have THREE spells. One, two, and three. That's it! 
If it follows the same rules as what they have shown us, each specialization tree I think will change they way we play a lot, but with only 3 new skills. They would have around 10 skills: 3 actives/spells, and 7 upgrades/passives. So these passives I think will be a huge change in gameplay, I think they will give major advantages (think on old sustainables).
I am sorry but I do not want you to be put down later. Necro I think will surely have 3 spells, and I guess one of them would be a "raise undead" or something like that. So that would leave room for 2 more spells. There is no way I think it will have "some entropy spells thrown there" or something like that, since there is no room.
However, among the skills there can be a lot of interesting stuff: a passive that gives you health/mana from nearby corpses, a passive that gives you a debuff aura (miasma for example), etc.
The specializations can be really cool and interesting, but keep in mind the number of spells I think will be limited severely from DAO.
Of course I miss having more spells and combinations for the basic trees, but I really like the idea of specializations with passives. I need huge changes in the way my character plays from the specialization, independently of the skills I use. A templar I think will have a HUGE magic resistance, a knight enchanter I think will have a HUGE boost to melée damage, etc.
P.S. Necromancer spec interests me. How is it going to work without sustained spells? Will Raise Undead be a time-limited active you have to recast all the time?
If I had to wildly guess, I would say:
- Raise dead spell (focus if it is a good asset, regular spell if it is just a trash mob to offtank)
- Debuffing passives: miasma, ultramini death cloud, chance to apply a debuff when auto-attacking or casting a spell, etc
- Necro passives: taking regen/mana from nearby corpses, doing more damage to undead or causing them less aggro
One thing that I'm very curious about is:
We've seen quite a bit of the Spirit tree, but there are two spells missing from it that I would have expected: Seeker's Swarm and the Teleport/Blink move (especially considering Blink LOOKED like it had the same kind of green energy as spirit spells/the Fade.
I wonder if there's a general tree...maybe combined with Mark of the Rift and all those? Sort of like Arcane or the Mage skills in Origins.
This is my confusion I keep coming back to: if there really are only 4 trees, and one each was an element, than we have no room even for Spirit or the Inquisitor tree we've seen...or what was that purple icon in the old demo? And what about the Cthuluhu Skull (Horror Icon I am convinced was Entropy)? The idea of there being only 4 base trees with 7 total with specializations does not fit with what we've seen (albeit in demos).
For reference:
http://i498.photobuc...rk/specDAI1.jpg
Winter (Snowflake)
Inferno (Fire Burst)
Spirit (Blue-Green Book)
Inquisitor (Green sowrd and eye); could have been Warrior Specific, but I doubt it, it's too critical for story
Green Bloom (I think Creation, and MAYBE Earth was lumped into this tree)
Suggested as Specializations
Sword and Shield for Knight Enchanter
Purple Thingy: Suggested as Necromancer
Cthulhu Skull (I can't spell Chthuluuhulluhtlu)...I think Entropy, but could be Necromancer
Even if we look at what seems to be the base mage trees, we're over 4 trees, and we STILL don't know where Seeker's Swarm goes (could be Inquisitor, as mentioned).
So confused... O.o
This is why I think there are 2 likely explanations (I think about this too much):
1.) Inferno and Winter are like basic weapon trees for other classes, and the other two are Creation and Entropy (that combine Earth and lightning into them respectively).
2.) I prefer this one: Mages get more trees since they live and die on their abilities more than the others (particularly Warriors): Base trees are: Inferno, Winter, Tempest, Earthquake, Spirit, Entropy, and Creation and then specs. That would definitely be a lot.
Noteable absences: Walking Bomb is apparently Mike Laidlaw's favorite ability, and we haven't seen it ANYWHERE (not even in Spirit, where it would normally go). Crushing Prison (Iconic and a fan favorite).
Speculation warning!!
I would guess this is due to the order in which they create and decide content. First the developers I think created a lot of spells which are cool and want to show, since I think they believe are fun, and innovative, are important, take advantage of the frostbite engine, are lore-imposed, or whatever. And then I think MUCH later, I think they have to create the skill trees and decide how to organize the spells, how much power they give to each spell, etc.
Evidently I think they did not think at the beginning "we are going to have a frost-only tree". No, they just created content and worked, and at one moment I think they saw they had enough spells, I think they did not have time for more, or did not want more, and that they had a lot of frost spells and fire spells. When they started organizing the spells, I think it made sense to put all fire in a tree, all frost in a tree, and I think they saw it was good. The "Discord / Discipline" temporary trees I think were born. But then I think they thought that since they already have 5 fire spells, and there is only room for 5 spells in any given tree, it would make sense to call it something more mass-friendly, like "Inferno" which is awesomely appealing. So I think the Inferno / Winter trees were born. But heck, we have in the winter tree a blink/teleport and a seeker's swarm (element given by staff), what do we do with that?
And that's it, I think we have no more clue to speculate further. I think It can happen a lot of things, for example:
- Let's call the blink spell something like "freeze time" and give it a lorely solution so the spells remains the same and it is a blink spell.
- Let's impose frost element to seeker's swarm, instead of letting it be decided by the staff.
- And a huge lot of etc. Maybe they even destroyed the Winter tree and called it discipline again, and leaving inferno. Who knows?
That's sort of my point - I think we're drawing too much from demos; they're incomplete info. Granted, it's all we have except two shots of Inferno and Winter.
@Andy69156915: I realize Spirit took over healing, but that's not all Creation was. I cling to the idea of Creation because of that green icon, and we could still have: Glyphs (Paralysis and Repulsion, for instance), buffs like heroic aura, spells like Grease and Stinging Swarm. I suspect they'll throw Earth into that mix and make it a nature school or something.
I think you are correct in the first sentence, indeed we are drawing too much from the demos. Just think that every icon is a placeholder.
However, I think we know more or less the amount of spells we will have, and I think we haven been shown a lot of them. Always basic spells, never specializations. I would not think about the creation thing, since we know we have:
- A full inferno tree, with 5 fire spells: flash fire, fire mine, wall of fire, flash burst and firestorm.
- A winter tree, with 5 spells although I think this are less final: winter grasp (/cold snap), wall of ice, frost glyph, blink/teleport and a final one (we guess focus-blizzard, but I dont think it is confirmed)
- A messy lightning/entropy one, which included: chain lightning, lightning bolt, static cage, focus-haste, and a misterious one.
- A spirit tree with: barrier, dispel, and tree more spells.
And I think that's it, there would be only room for 5 more spells in that setup.
However, we know there are also the following spells: seeker's swarm, mind blast, stone fist.
Initially the discipline/discord trees had 6 spells, but when they turned them into inferno/winter they had only 5 spells. And we saw a pattern, where the final 5th spell had the requisite of getting all the tree's skills. This kind of screams "INSERT FOCUS SPELL HERE" to me, and judging by the placing of the haste spell (only focus confirmed spell) in the entropy tree, I think it matches. So I think we would have firestorm as focus, blizzard (or whatever frosty one) as focus, haste as focus, and another as focus. Since I think mind blast, seeker's swarm and stone fist are not focus, I think this would mean that of the 5 spells not-confirmed, I think we would have 2 more focus (blizzard?, spirit one?), another in the entropy tree, and I think 2 more in the spirit tree.
So I think we need room for 3 spells, and I think we have room for 3 non-focus spells.
To sum up, if there are truly only 5 spells per basic tree, I think we already know all the spells except for the specialization ones.
If you are a pesimistic, I think this is it, there are no more spells. Live with it. And I think those 2 other trees are going to be a little mess (they have to separate into 2 trees: 3 lightning spells, haste, mind blast, stonefist, barrier, dispel, seeker's swarm and a focus new spell (supposedly to heal/revive).
If you are optimistic, I think there might be more spells, and then I think we have 2 options: Each tree has more than 5 spells (and maybe they go back to discord/discipline), or maybe mages have 1 more basic tree and organize spells better with 5 spells per tree. But please, remember I think we are taking about a couple more spells, not much. Keep your hopes balanced!!!!! 
And also, please, remember the spells have not been confirmed. We just saw them. Maybe they totally remove one, like seeker's swarm or lightning bolt, in order to make room for other spells and leave a coherent and consistent skill trees system.