I think Ash was funnier back at the beginning of the anime. From season 4 to 13 he was getting stronger as a trainer, but it took away what I liked about him back at the beginning: he was dumb and funny. That's one reason I have no trouble with the way Ash is in Unova now, because he's gone back to being dumb and funny. I missed that a lot. So, I didn't like the first change in Ash's personality, but I like the second.
Team Rocket's change this region to being more serious has been great, because it's made them a stronger team. That's one personality change I like.