Statistics can very well lie... its called inaccuracy and unaccounted variables.
Just because a champion performs extremely well does not mean he is broken. If statistics point to him performing extremely well then someone must takes those statistics and find logic behind why they are like so. Why does he perform so well? Does it have to do with current meta, build trends, play styles, specific points during the game, etc.? Is there a niche role he is extremely powerful at?
Rumble is strong, very strong really, but he is most certainly not OP. MF is basically in the same state, tho I would argue a bit lower on the totem pole then Rumble yet easier to perform well with then the skill level needed for Rumble. TF isn't OP... he just has a nice kit that lets him do stuff at the loss of raw dmg that would otherwise need a mixture of play styles, champs with supreme mobility and reach, and wards/clairvoyance/etc. to either replicate or counter. Conveniently enough everything he does can be replicated by a team to either match or countered without actually picking TF.
Map wide awareness... wards/clairvoyance/certain abilities. Not being vulernable to instant ganks by playing safer and having other lanes/jungler follow up if jungler is moving to say... bot to create a 2v4 as well as using teleport (not as flexible), boots of mobility, Kass ult, Nid pounce, etc. Poke.