Just picked up Dragon Age yesterday. I started with a mage, although not sure that was the right move since they can be a tad fragile. I played a mage in WoW so I always like to see what they can do.
I find any character works with the right party balance. I play a rogue and the party that has worked for me is a heavy armor sword/shield warrior, a mage focused on crowd control (cold/tk/sleep), and a mage focused on heals and buffs. If you've played enough to have all the companions you can guess which three I use as my normal party.
Mages are highly overpowered, especially near the late game, so Psychonaut, you should have little trouble once you get past those first fragile levels.
I fucking hate Oghren and I resent being stuck with him for that section of the game when my party is set up around Alistair tanking and I have all my coin invested in his gear.