I would also like a "Legendary Egg" that can spawn random legendaries, for like... Servers and such! Or a boss spawner egg too, for servers!
I also think it'd be great to have a bag or backpack. Could be worn on the cape layer? (I think that's in 1.12,) That would be an extended inventory. There's soooo many items in Pokemon, there's a reason the bag exists!
Maybe some more NPC interaction? So far, they just talk to me. (I have no idea if there's plans for like... Team So-and-So yet) But if you're just playing single game, it seems very vast and empty, even with some of the pokemon.
Last thought is maybe a radio that plays some of the classic Pokemon tunes? Something you could carry around (especially if the backpack idea is implimented) or could have covers. There's plenty of fan-covers on the web, and of various Genres, or even look at good ol' "Overclocked Remix" for some.