From what I've seen so far, I'm pretty disappointed in how they've handled mages. The DA team created some excellent lore regarding magic. There are four schools: Primal, Spirit, Creation, and Entropy. The schools the Inquisitor is familiar with seem to be Primal (75%) and Spirit (25%). Yes, I'm sure some Creation and Entropic magic will be integrated into other spell trees like Necromancer or Rift Mage perhaps, or even the 5th starting tree the mage gets that has to do with being marked by the Rift (we're still not sure if everybody shares the same one or if that's just the Warrior who gets that particular one). Also, I'm sure some of the Entropy or Creation effects will be integrated into the elemental tree abilities in some cases.
It just feels like a missed opportunity. 4 main schools = 4 starting spell trees...doesn't that make the most sense? Furthermore, mages started out in the DA franchise as a completely different role than what they seem to be fulfilling now. They used to be much more focused on buffs, debuffs, and support abilities for the entire party; now they seem to be much more about dealing direct damage. If I wanted to play that way, I'd play as a Warrior or Rogue, or spec an elemental mage.
I don't know if this is valid because there's still a lot we don't know, but to me it feels like the support role is being edged out in favor of allowing all of the abilities in this game to make the most sense for multiplayer... 
Hey now, Multiplayer is not going going to affect single player ! Didn't you get the memo ? Bioware has said this before and it must be completely true ! This new approach is all about tactics, choices, strategy, freedom and role-playing ! 
*end sarcasm*
One of the main selling points of the mage class is flexibility and choice. By this I mean magic itself is very flexible and diverse.
You can accomplish something either with the manipulation of the elements, the manipulation of the spirit, the manipulation of blood, the manipulation of mind, the creation of force, the summoning of ally, the enhancement of the environment.
There is a reason why when you say mage, it can mean many things from wizards to sorcerers to warlocks to hedge mages to illusionists to summoners to healers to battlemages to nightblades to elementalists to witchhunters.
Wizards are the genius student, the one who studies for years to become the best. Sorcerers are the natural prodigious arcane masters. Warlocks are dark wizards. Summoners are conjurers who can conjure anything from weapons to armor to beasts. Healers are mages who specialize in healing and restorative magic. Battlemages are mages who wield weapons, use destructive magic and wear heavy armor. Nightblades are a mix of mages and rogues, where they use illusiory magics to augment their speed and stealth. Elementalists are like Avatars, masters of what we perceived as elements in the ancient times and in the middle ages.
What Dragon Age Inquisiton seems to be doing is greatly limiting all of that in favor of making every mage primarily elementalists with limited support and only three archetypal specializations. I don't you about you but in a world that is much bigger with more NPCs, you would expect moar specialization options, more diverse schools of magic. You would expect the Circle Mage to have different skillsets as opposed to the Dalish Mage and the Qunari Mercenary Mage.
"Ah yes, lore. The building block of a role playing game. We have dismissed the claim of its existence."
Fire, lightning, earth and ice can be grouped under the Primal school with fire, lightning, earth and ice causing different side effects.
Fire causes fear and DoT, lightning shocks & drains mana, frost slow / paralyzes & drains stamina, earth knocks enemy down & can cause poison DoT.
Why they gave all three different trees is beyond me. They could just have had an Elemental school tree or Primal school tree where you have spells like Elemental Walls, Elemental Seeker Swarms, Elemental Rune, Elemental Enchantments, Elemental Storms and then have a main spell that allows you to invoke fire or frost or lightning or earth elements. That would have made more sense.
Similarly creation and some element of the spirit school could have been expanded and given more utility. Restorative magics should have been used to boost allies, attack undead (life restoration is the antithesis of death), summoning benevolent wisps and spirits to aid in fights. Entropy on the other hand, could have been used as the debuff / socially allowed dark wizard tree. Weakening, debuffs, hexes, curses, morphing enemies into harmless forms, health drain, etc. Again, this would have made more sense and be more of an evolution from DA:O and DA2 as opposed to just randomly combining them with elements.
What they are doing now screams poor design choice and streamlining. Of course, of course, this is all in the name of freedom and more choices.