Judging by the comments on the strength of the soul being used to cast more powerful spells, presumably the strength of your soul will be a stat determined at character generation. So warriors might be able to cast minor spells like arcane shielding or whatever it's called.
I see that there's no option for 'No expansion packs'. I prefer games to come feature-complete at launch, or have new features added via patches like Valve games.
I love the idea of turning a previously-cleared dungeon into a hideout to stash all your loot and stuff. Perhaps you could even set up a camp in the upper levels of a dungeon to rest up before taking on the depths.