I personally have always had problems with abilities below 10, save at times a 9 strength for a non melee type. I find it very limiting as a roleplayer to play someone that is dull and dimwitted. I know many players seem to ignore the lowered mental abilities and play a character like that as normal. As a GM I have forced players to adhere to written and suggested guidelines on say
a 8 int --- "roll to see if you can remember the plan"
or a 7 wis --- the classic Leroy Jenkins all the time
This is just me of course and I have no problems roleplaying with a character like that just to see how someone could make it work.
I agree with you there... I hate having mental dumpstats for that reason. Though it's also the reason I don't like barbarians... the rage feature that turns off parts of your brain doesn't appeal.
So far I have two notions:
A sorceress with the elemental fire bloodline for lots of blasting and the "barely-clad, naughty mage" concept, one who might not be from the Shackles at all, but arrived recently seeking lore (as there's a lore-seeking background). Possibly with a devil-touched background to explain the fire instead of an elemental, but that's just flavor.
Big, buff, Amazonian fighter with a big sword or axe, two-handed wielder. Probably human, unless I can somehow make a balanced minotaur or minotaur-like race. While this is a friendly game, I've read that fighters are very low on the class tier... and she'd just be wearing light armor, which is letting an important class feature go unused.
Also, DM question: Are we using background skills?