I can understand why if an owner of a question updates it, it should give the question more attention, and if a question has no answer and someone edits it making it more clear, it would make sense to display it on the main page again.
But in most cases, edits are rather trivial; fixing typos, grammar, phrasing, etc. Sometimes people edit old, answered questions and they get front page attention in place of new ones. Should it be this way?
I think edited questions should be bumped to first page only if they hadn't been answered yet or had been edited by the original poster.