For me the mage trees kinda suck. We are pushed to "the best" trees by the design which are: Fire and barrier (I called it barrier instead of spirit because it seems to exist only for barrier spell).
Fire got the highest damage potential (fire mine 1600% weapon damage compared to avarege of 300% - ridiculous), as much cc and combo potential as other trees and best offensive passives, while barrier seems to be a must for every mage. While lightning seems somewhat ok, frost is most underwheling. With little to no damage, it offers no better cc then the other trees. Wall of ice seems to be painfully situational and blizzard's damage is most disapointing.
Had there been no 8 active abilities limit, I would see the ice mine (ice mine, fire mine? since when are there mines in DA universe?) as a glyph of paralysis, useful. However the 8 active abilties limit makes me think of it as useless, there are several other spells from other trees that offer far more for a lot less points required to unlock them. Besides, whatever happened to ice burst (was shown in PAX 2013 demo) is it an upgrade to winters grasp?
I planned to make a winter/storm mage (or winter/rift mage), but looking at the trees I can't help but feel like taking spells like wall of ice and ice mine makes sense only in preparation for combat. Placing ice mines on the field (I wonder if we can create more than one) block some enemies with wall of ice and then swap with spells that actually can be useful to me in fight. Which means SWAPPING ABILITES BEFORE ALMOST EVERY FIGHT if I want to play tacticly.
However by the looks of gameplay vids, resistances and immunities are very popular throughout the game making more specialized mages useless a lot of the time. Which reduces the mages to be reliable only as barrier spammers.
From game to game BioWare is weakening mages more and more as if Dragon Age was an MMO with PvP. Gives rogues and warriors ridiculous flashy abilities that make them look like mutants or mages (warriors making walls of fire and summoning rocks form the ground?). In DAO besides the graphic representation of auras warriors and rogues seemed more like skilled combatants rather than mutated frogs or wannabe mages.
After all this I am yet again reminded of gameplay vids and their new healing system (you can't use healing spells, besides the focus group heal, but you have potions with no CD that you can just fasttravel for, plus they said that there will be healing granades too). I get an impession that in the end character's buld wont matter, because whatever could work since there is really not that much actual dfficulty, Inqusition perks will give you more potions, you spam barrier enough and the autoattack will do the work for you, spells and abilites are there for a pinch here and there but you MUST have warrior, rogue and mage in your party. Not only you need them to complete side quests (mage energize, rogues picking locks and warriors kicking walls), but their even more seperated into roles LIKE IN AN MMO.