How about this instead of bans in ARAM?

So, Riot made it clear they won't unlock every champion in ARAM and they removed bans as well.

Now I am thinking about a cooldown system for champions. Something like: when you played a champion then you cannot get the same champion for 10 or something games. Idk the most reasonable number but it could prevent ARAM-only accounts to abuse the same champions in every game while other players could get strong champions whenever they aren't on cooldown. So ARAM would remain all random, no bans, yet ARAM-only accounts would not have such a huge adventage.