DISCLAIMER : I've already made up my mind about TFT in its current state, so if you're here to argue, keep in mind I won't bother myself.
Aside from its RNG nature, TFT also comes with a plethora of bugs that can and will cost you rounds or games even. The worst I've experienced so far is your champs simply not doing anything at all. Clearly there is some issue with targeting, it's trash to begin with, but sometimes a champ will sit still and wait to die, despite not being subject to any CC whatsoever. Other times it appears that champions switch aggro for no good reason or entirely ignore champions in favor of someone else. A teamfight sim where not only is aggro automated, but sucks, too. Marvelous.