Automated endgame PVP content.
The problem with our endgame content is that it's Battle Tower, Official Events, and collecting shinies.
Battle tower is rather boring and tedious because it's an AI.
Official Events need to be pumped out constantly manually by staff. There's not even any sort of coded support for them. They're not automated. Not many people are aware of them. We only get a ridiculously small amount of the playerbase to participate in the (aka 30 people).
And making comps simply doesn't really contribute to collecting shinies.
What we need, I think, is stuff like this:
-Automated matchmaking. Much like what we already have, but with actual incentive for everyone to play. Aka, get rid of ELO or whatever is currently used, go for a League-like tier system, with manageable goals. So people don't think "Time to climb up the ladder and be #1" and can settle for "Aight, ten wins and I can get promoted to silver!"
-That old PVP Battle Tower idea that went sort of like "If you win 8 battles in a row you get on the leaderboards and a prize, happens at prescheduled times"
Anyways, these are on the top of the priority list imo, because working for months and months on end for hoenn gives players five more days to complete the storyline, collect some new pokemon again, and there goes the content. Only grinding is left.
Automated PVP content keeps people busy endlessly even if we were to never run an event again. Not that we'd do that. Automated content is just what makes the game stand on its feet.
[spoiler] ...And maybe exact IVs [/spoiler]