Obviously, what kind of questions you write has a major effect on the event. Hope this helps. That's when a speaker's real analytical skills are tested. I think it still sounds a bit like too much of what we've got. I like this idea, but I also see a major problem.
Philosophy is a very individual based thing.
Everyone has completely different philosophy. For example, I don't believe in burial, I personally think we should ground people into fertilizer. Well, while this may fly in my mind, and I can make a solid basis for this in scientific reasoning, if I get the wrong judge with a completely different philosophy, no matter what your judging scheme is - I would get slaughtered. In the end, the event would become what your problem is with Imp. I do not think that all judges are intolerant of opposing opinions.