Minigames are better then a tutorial.

Ai vs Bots is only as helpful as the level of skill bots can play. It does not provide adequate instruction.

Breaking down mechanics into games that reward proper usage of mechanics is probably a more effective way to bring new players up to speed for basic understanding of the game.

Also Rentals should be looked at to provide new players some better tools to catch up to gap in content on accounts. As they stand I think there is almost 0 incentive to use a high BE value shard on a rental. Providing some BE or keeping the ability to upgrade to a Permanente at a discount during the rental add value to newbies.

If your new to mobas and want to get good at league. Your gonna have a high burden of knowledge. You might want to start with Battlerite to get a good feel for skillshot combat.

The next tutorial attempt riot does should isolate the mechanics needed and be broken down into subsections to help train mechanics.