[NEW MODE] COOP Missions (Lore driven scenarios)
I thought about this earlier while playing Starcraft 2's Coop Commander mode, and given league's rich lore (or potential for it rather)... this would be the perfect way of bringing lore to the game. Very recently, Heroes of the Storm released an "Escape from Braxis" scenario, where a team of 5 players needs to escape some infested facility, and it requires some focused teamplay to successfully pull it off. Not everyone wants to play a super competitive match (PvP can get very intense, and I'm not always in the mood for that). There are a ton of players in COOP vs ai for this reason -- some are practicing, but some just want a "beat up the bots" mode.
Given how successful the latest Star Guardian scenario was, I know the devs have it in them. I missed the battle boss arcade event, but I think this is also similar. Unlike starcraft 2's commander mode (where Kerrigan is teaming up with Dark templar in random scenarios), the scenarios would give you a pool of characters to choose from that would be appropriate to the story they are trying to tell (similarly to star guardian, you must pick from 10 guardians, and their skins are locked to SG).
Here is the idea. Create a bunch of scenarios: Invasion of Ionia, The Fall of Icathia, The Rise of Shurima... whatever (there are so many races/nations/stories that could be explored)... And allow players to queue up for specific missions (selecting Normal or Ultimate difficulty), or let them just pick "random scenario". These scenarios don't need to have 5 players per team. Some scenarios could have teams of 2, say Draven+Darius are off on some adventure where Urgot has laid some trap for them to get revenge or something... Other scenarios could have 12 players queued up together to have some sort of epic helms deep type defense scenario (say, Ionians defending against noxus invasion) (We've had 6v6 before, so yes it could be done).
Once the players are matched, say they are matched into "The invasion of Ionia". Your team picks from Ionians only. You then go through different levels (like star guardian) where there are different goals. Some are defense, some maybe require you to attack. etc. At the end there could be some boss encounter. Throughout, you could be facing mini verions of different champs (say the soldiers are all darius') and the final boss can be some doom version of Swain.
Other maps could put you on a large map, say like summoner's rift size. You could try to win by holding the walls, falling back if you need to while the enemy sieges, with an alternative win condition. Perhaps you could have your assassins try and sneak through the jungle and assassinate the enemy captain.. providing risk/reward. Whatever.
The point is, League has a very rich lore, but nothing is done with it. A lot of players would love to experience it first hand, and I think this could be the perfect way to freshen up league... probably even bringing back a lot of old players.
Yes, PvP 5v5 is the bread and butter of league (even though I love 3v3 too, but I'll leave that out), but I think this is a mode worthy of being permanent. It wouldn't detract from the main game too much either. Once you beat all the missions, you'll need your fix of PvP again, but it would be nice to be able to experience the world of league in a more meaningful way than just looking at the characters, and using your imagination. Let's be honest, Riot has the resources and the talent to make it happen.
Imagine star guardian was something relevant to lore, they could just keep it on the roster of coop maps. Maybe creating a new one every 4-6 months -- releasing some skins, premium chests, etc etc, to celebrate the event and get people to spend some RP. Yes the maps would be free for all, but it would go a long way of fostering a new and fun way to play with characters.