What Enkatreia says makes sense. I'd like to say two things though.

First, couldn't both of the problems with the options you suggested be solved by adding a specific "Disruptive Behavior" category to the vote kick list, and then barring anything outside of it? That would allow for a fluid category to always be applicable to that "one more reason", while keeping players from being able to try and claim that it's okay to throw someone out because their gear is good enough to be in the dungeon but not good enough to effectively speedrun.

Second, I think another problem being brought up in this thread is a perceived lack of action on the part of GMs; there seems to be a clear feeling that -GMs- are using this ambiguity to not investigate situations properly (as potentially illustrated by the opening post, though of course we would need more details to see for sure). Whether this is right or not it's an attitude that seems to be prevalent among the playerbase, and while I admit I'm not really sure how it could be, it seems like it's something that should be addressed.