Zilean's Bomb: I play zilean a lot, he is in fact my co-main. I play him AP style and blow things up. They recently changed his bombs, and while I don't like them nerfing the damage ration, I can accept it. The thing that annoys me is the ticking damage that counts down the spell. This is absolutely annoying, I can no single bomb heroes at towers, because I now do a whole 1 damage to a hero so the tower beats me down. It also ruins placing a bomb on neutral creeps then scooting away as 4 seconds later you get experience and gold.
Taric's Ult: Taric is my other co-main. I only have one problem with this skill. I can't turn off the skill when I am CCed. I would love to be able to turn off my ult when it starts draining 150 mana a second, but then I get stunned and no longer have the mana to stun the other team.
Well that's it really, I don't really post much but I would really like to see these things changed, especially Zilean's bombs.