I love riot, but they implement a lot of unfinished features and that needs to be fixed.
Honor system: Partially implemented, left to stagnate, now it's rare to ever see anybody with a ribbon just due to how broken and buggy the system is.
Champion mastery: Interesting, gives you a great feel for progression, but absolutely lacking any sort of real substance.
Chroma's: Would have been an awesome thing to tie to champion mastery, but they've been left to stagnate and I can't remember the last chroma we had
Twisted Treeline: They said a year ago they were going to start cleaning up the bots in twisted treeline and make it playable again, but it's still unplayable and filled with bots, which is a shame, because I really want to play it. But it looks like twisted treeline is going to end up going the way of dominion at this point.
Even the new hextech chest system. Like, can you at the very least make it so I can't get champion shards for champions I already own? It already takes forever to earn keys, it would feel a lot better if every other chest wasn't a dud as well.