Idea for a new game mode: Castle Defense (PvE Team Vs Creep Waves)
Back when Warcraft 3 and its custom maps were a hot thing, LoL had its origins in a custom map called DoTA.
There was only one other custom map that I think I enjoyed as much as/more than DoTA, it was called Castle Defense. I wish I had an authors name or something to attach merit to, but I don't.
Basically, the map was set up like a castle/fortification where creep would approach in a raid style and players would assist limited amounts of NPCs against progressively harder and harder types of creep waves.
Like the Dark Star Karthus map, I think Riot could make some sort of a weaker hero characters that had some abilities like maybe repair turrets, or a heal to heal the limited friendly npcs. Stuff like that. Maybe even have like a "protect this npc from dying" character inside the fortification, and fit "the event" into the lore somehow.
Anyway it would be a pretty neat reprieve from the sometimes tense nature of PvP play to work together and see how long a team could hold out.
Thanks for reading my idea!