I agree with OP. We should have ranked ARAM before we have ranked TFT. Ranked TFT won't signify anything.
Right now, it's a pleasant casual game with almost zero toxicity. It doesn't need to be more competitive.
I feel like, instead of pretending that some skill is involved, they should continue with an option for a kind of gambling system, where players can bet tokens or BE. The size of your purse (or your total winnings) would be plenty indicative.
I'm in matches and players occasionally grumble on what they receive. I ask them if they also complain at a casino... (many do, of course)
Because, given any setup in TFT, the choices to give the player the best chance of success are calculable. A computer could play this game. It wouldn't always win. But it would have the best chance for success in any match.
The real skill would probably come, as with backgammon or blackjack, with managing the betting cube over dozens of games.