[x_Dragun_x]

Well the thing with trundle is, He is just a right click champion. I mean sure he can do some good damage with his contaminate, and he can create a small wall, But besides that, he has no other utility, and nothing to benefit the team.
His rabid bite ability saps a bit of damage, but with merc treads it isnt that long, and late game is barely noticeable. You can simply slow trundle/stun him, and move out of his contaminate in order to avoid his speed boost. And if you can get around his pillar, there is nothing else for him to do but chase after and hopefully land a hit.

I mean sure, he can put out some good single target dps with his rabid bite+t force, But thats only on 1 target, in a 5v5 that dosent help the team much, since he dosent have a catching ability, like a flash/taunt, he can slow them, but he can be slowed just as easily by any other carry he is looking to get.

The only "Good" Thing about him, is his ult on a tank. It makes him much beefier and allows the team to take a tank down quicker then they would have, But after that duration there arent much other uses for it.