Now that the skill system is coming into focus, I'll venture a few opinions:
Likes:
1) No regular healing spells and limited health regeneration. Makes potions and situational healing options (like a Focus ability) relevant, makes responsiveness and preparation in battle really pay off, and frees up your options for party composition (no longer need to consider bringing a healer along).
2) Guard is a really cool mechanic for Warriors. It complements their playstyle perfectly: you are rewarded for fast reflexes and/or tactical use of stamina with extra health. Even a two-handed Warrior can tank nicely if they play well enough. I like Barrier for Mages and the evasive/escape options for Rogues too.
3) The skill tree layout is nice. It allows more flexibility than DA2, and it seems like your options branch out from the skill you are on to any adjacent skill; you no longer need to have both pre-requisites in order to get a skill, just one. For example, you can make your way down the right side of a skill tree, skip the first skill on the left side, then cut over to the second skill on the left side if you want. Also, you don't seem to need a certain number of points in a skill tree to purchase a new skill or an upgrade to a skill. That was super annoying and limiting in DA2.
4) One specialization option is the right move. It makes you more unique (dare I say, more "special?"). And you can really focus on honing the area you're interested in.
5) The 8-ability limit seems to work well in the context of the combat system Bioware designed. I still think it would be interesting to see a combat system more akin to DA:O taken to the next evolutionary level, but mayhap that will occur sometime down the road. I like DA:I for what it is. They've taken good ideas from a variety of games like Kingdoms of Amalur, Diablo, and Dark Souls, while at the same time retaining the essence of Dragon Age.
6) Personal favorite abilities: Rogue = Longshot, Throwing Knives, Poisoned Weapons, Leaping Shot. Mage = Ice Wall, Blink (or is it "Fade Step" now?), Dispel, Barrier. Warrior = Shield Wall, Lunge and Slash, War Cry, Holy Smite
Dislikes:
1) Basically the entire Two-Handed Weapon tree other than Block and Slash (and maybe the Berserk one at the end of the left side, but we haven't seen this one yet so idk). I hate the animations of Mighty Blow and Earthshaking Strike. They are so over the top and effects-heavy. Reminds me of a funny scene I witnessed in one of those Twilight movies where a dude punches the ground so hard that he rips a hole 100 ft into the earth then throws people into the molten lava now exposed (the only reason I know about this is from RedLetterMedia's review of the movie, so don't judge me!). Whirlwind is ok I guess, but I'd prefer the Two-Handed tree to just be a variety of super-powerful weapon swings/maneuvers that aren't visually cluttered, but have a nice variety of effects like stun etc.
2) The elementalist Mage. Way too many Mage abilities are fire, ice, and lightning. I'd like more representation from magic schools other than Primal. That being said, most of the abilities themselves are pretty cool, and the specializations may make up for this a little bit (Necromancer = more Entropy/Spirit magic?, Knight Enchanter = more Creation potentially?)
3) Bioware being coy with the skill trees. I wanna know everything! (this is a non-serious complaint)