Hood's Invisibility Cloak
I was playing with Hood in arena today and was thinking, "Why doesn't his invisibility work 100% of the time?" When you think about it, it really makes no sense that you can get hit... I mean, he's invisible! I think it would be a small but great change if attacks missed him while invisible 100% of the time. It would make a mediocre champs just a bit better and way more fun to play with.
Also... If Hood's cloak is one of the Deathly Hallows then there really is no way he should be able to be hit while invisible... Food for thought.