Hmmm, I didn't find the start to be overly difficult personally. Especially if I had a party member, ANY party member with me. Slide in behind the guy and you can deal out some pretty sweet damage. Toss in a stun after a few hits to make sure they don't turn around. I did have some growing pains at the start, but that seemed to be more related to the group as a whole and me not expecting that the game might be somewhat challenging.
Hmmm, didn't notice that. Especially once I got Alistair up to tanking form. Alistair typically hovered around 10-15% of all damage done in the party, while Morrigan and myself each split off about 40% each. Though I tended to put my points split into Dex and cunning, with some strength and willpower. Though I used the strength so that I could get swords, not so much better armor.
I found the social skills to be pretty useful. Which situations did you find you fought the guy later with more reinforcements anyway after using them? If that happened, I wonder if you actually failed the Intimidate/Persuade check. And yes, if you don't put points into lockpicking or cunning, you're going to struggle with opening locked items (I think it also helps with spotting and disarming traps too IIRC).