I'm pretty sure you can get by with gimpy stats, the game isn't difficult on normal or hard.
My rogue had very little strength (read: she wore robes instead of armor), and simply stacked cunning. Carved shit up and ran like a bitch when shit got heated. Talent stat requirements will pretty much give you basic stats you need to perform.
Also, note that dexterity doesn't work as it should, there's some hotfix floating around, but it makes the game overall harder because 92% of the enemies use bows. As such, I would advise maining as an archer (though you should still carry a ranged weapon and use it to pull mobs into an ambush).
As for difficulty, the game is hard until you figure out how to play, pretty much. Also exponentially difficult until you get a mage that is specialized into spirit healer.
Now that I think about it, most "permanent consequences" are probably about not taking possible party members. I uh, might have killed the naturally-specialized spirit healer on my first playthrough.