Leveling
Leveling a new account has been by far the most painful process. You are given NO control over your runes, summoners etc... the matchmaking is absolutely horrific... Sincerely think this is why the game is loosing player base. Getting matched up against smurfs with actually brand new players on my team.
Not only this, the lack of role picking in the first levels before you're allowed to draft pick.... there should be a better way to have veterans be able to just play normally. Like an arcane comet default ezreal..... no... just no....
and also, if you sort of know how to play, you get paired against assassins with flash and ignite... and you're sitting there like a teddy bear with heal and ghost.
This is from the standpoint of the game losing new players.... you get a 25 kill riven smurf against a brand new kid.... extremely hard to have fun this way.