So I found out that tactics pretty much make or breaks the difficulty. If you're not doing well you're probably needing better utilization of the \ screen. This is all on nightmare.
I tried an experiment, where I programmed my mage to focus on healing as a first priority, then petrifying bosses and > elites, sleeping melee attackers, buffs to reduce spell and regular damage, stone armor, and exploding those far away with nukes so I wouldn't friendly fire. I focused the warriors on taunting and shieldbash/knockdown chaining.
Now I CAN leave my mage run with the AI, while I run around as warrior taunting everywhere and shield bashing.
I probably still wouldn't start nightmare without a decent mage though. :/
The story itself is alright so far(haven't played much), if you can sneak away a bit of disbelief at how conveniently things fall together or apart, or how stupid some people are or plot devices that force you into situations despite the choices you make.
EDIT: Also if you have a legit copy, new patch makes Easy mode EASIER, and makes your party do more damage in normal mode. Hard and nightmare remain rape however. Kids these days
With only a few builds I can see being viable in nightmare right now, the game is starting to feel like single player guild wars tactic wise. Disabling enemies so you don't get swarmed is key. Damage reduction is key.
Really funny spoilers for cheap/free stuff
After you come back from the quest the Grey Wardens give you, before you do the "joining", take all the armor and gear from the other two guys. They don't survive but this way you can sell their stuff for $$$. Alistair is a permanent companion however, so anything you give him sticks throughout the game.