In the last few games we played online we determined that for TT ranked, there are some champs that should be damn near perma-banned:
Rengar, Tryndamere, Eve, Kha'zix, and Jax.
These champs snowball so hard it's not even fair to play against them in ranked competition from my experiences. So far I'd have to say also that Mundo, although a monster in 3's, isn't bad enough to be banned. Same applies for Teemo, he's annoying but can be dealt with.
For comp overall it seems that bruisers win the show, a good Olaf, Irelia, Shyv, or Hec can really carry the team.
I'd have to say though, that if you want to see something funny, put Singed and Mundo on bottom together. Slows, stuns, poison, and AOE damage for days.