TB is back to lvl25+, revert that before all your new players never learn lanes.
Sometimes, when you're Riot and your sole feedback is practically LCS Pros and famous players, you tend to forget about things.
I have a smurf and I noticed I can't play TB due to the level limit anymore, huge mistake. In blind pick, it's fucking blind pick and quite literally. New comers don't know what the fuck any lanes are and they go whatever, unaware and confused by knowledgable smurfs screaming or patinetly *attempting( to explain ANYTHING.
Throwing players at a literal blindpick mode (Or the bot infested ARAM/Dominion) will give them a extremely hard time learning, at least there's set lanes and people tend to be more smarter and not lane-dicks there.