Two weapon combo is the best if you raise speed REALLY high, I'm beating lv 57's at lv 30 right now with them, but you also have to raise STR REALLY high also, and you only need about 50 dex total to hit everything. Two weap is superior to 1 weap because of the stat bonuses you get from both weaps, shield builds will probably do well also since they can counter at later levels and shield bash is powerful, but with 2 weaps if you get combo x4, thats easily 400 damage per turn, and if you have 2 turns, 800 dmg per round (with me it would be 1200 dmg per round due to high str)
I'm not sure if this was seen before but dungeons would be nice. Also, extra challenging AI would be nice if rewards were along the lines of greater equipment (Green equipment with extra stat boosts)
A dungeon option with monsters would be a nice change of pace. I know this would be a LOT of scripting but it would be cool to loot chests and stuff like that.
The only stat worth raising is luck, since with all other stats, all it does is raise your skills, or health... but what do you need health for if you pick up a bunch of badass weapons?