Trying to figure out how much stuff needs to be wrapped up in this episode...
The May/Drew battle, duh.
Harley's plan - according to reports I've read, he's trying to upset May by making her and Drew fight. It's possible he's given up on this now, though, since he's already lost to her.
The May/Drew argument from the previous episode.
Drew's character arc in general.
The Drew/Saori tension.
Either a May vs. Saori or Drew vs. Saori battle.
That fricking Aipom. -_-
Saori(/Drew?) winning the Festival, the trophy being awarded, characters saying goodbye, etc.
Quite a lot, then. Though I think the writers proved last episode that they can cram a lot into twenty minutes. I just hope they don't uberfy Squirtle (if it knocks out Flygon, I'll break something), Harley doesn't fade into the background, and the Drew stuff is dealt with properly.