While it's possible to make your way past most battles, It's not quite 100% possible to avoid them all. But it is quite possible for YOU to avoid fighting.
Most scripted confrontations have at least the potential option to bribe, cheat, sneak or persuade your way through. For instance, with the bridge thieves you can either pay their toll, agree to blow up the other bridge, or trick them into thinking you're a thief as well. (Note that some options require an investment in Persuasion and/or Charisma; but as a talker, you'll be doing that in any case.)
Later choices may require a certain minimum Intelligence to unlock the dialogue options, or perhaps a spell to win them over to your side. Random wilderness fights can be "avoided" by save-skimming before you travel.
But there are a few spots — notably, side quests and specific mastery quests — where the only way through is with a weapon. Which is why you have followers, and give them the best weapons you find or can afford. Sit back and let them do the work; as a bonus, you'll even still get some of their XP (though not as much as when you wade into the battle yourself.)
Protip: install the unofficial patch ASAP; among other things, it repairs a number of broken dialogue options, include some that give you the chance to negotiate rather than fight. (I'm thinking in particular of a certain obstinate half-ogre, in a place you only get to visit once.)
Hope this helps. :)