The problem with defining this format by what is "fun" is that everyone seems to define fun as what they don't lose to. If you keep losing to easily answered cards, that means improve you should improve your deck. If you don't want to improve your deck, then you should come to peace with the idea that you are going to lose because you chose to not interact with better strategies.
Probably. He looks very planeswalker-ish. A Normal demon/devil doesn't look that human like.
Not to mention, so far planeswalkers have always appeared on the booster pack art. If Avacyn restored has at least one, may be 2 planeswalkers, I can't imagine that one would not appear on the booster pack.
He is a planeswalker, I'm willing to bet my card collection on it.