Their latest Hero designs have become a lot better I think. Leoric is a great Hero and I like that both his ultimates are used quite frequently. I think that it's because of their latest Heroes that some of their oldest ones are becoming a lot more dated and less viable. I honestly think Kael'thas and Butcher basically killed any usefulness a Hero like Arthas used to have, because he's just too slow to react to Kael's burst and is incapable of disengaging the Butcher in a reliable manner as well as being outhealed by him.