I hate/like(when I'm using one) the axew line, not because in design but when I'm battling one, they're a pain, same with Druddigon. Oh, and eelektross is annoying with levitate and made me want to chuck my DS across a wall. Basically, I hate tanks unless I'm using one.
The white treehollow was annoying because almost all the pokemon were carrying berries so my SE attacks couldn't do too much. And the veterans in Drayden's gym were annoying. I wish you could just push them off!