For me, like you, less of the repetitive story. It's just boring now.
'There's a new pokemon game coming out! With an original plot! It's really expensive, though...' *four-digit price tag*
I like the kiddy stuff, sometimes. It's fun. But that's just me.
Higher level pokemon in normal places, ability to go to the Pal Park without migrating Pokemon, at least a few more master balls (i'm just like that. XD), a Legendary that evolves (It would be, like, a pokemon revolution!
), good pokemon cries (I like pokemon cries that don't make the same sound as me whenever I cough. Or the windchime sound. That's just
dumb.) and ability to do some things alone that are usually done with friends. I mean being able to cook poffins with an NPC that helps you (you might even be able to rent them, like the more money the better the mixer) and traps and secret caves underground that are set automatically by the game so whenever you go underground without someone in a ten-metre radius it isn't tragically boring.
Got that, Game Freak?
I would take out Pearl, the annoying 'buddy' that you get stuck to by the hip at the start of every game.
Every time they see you, they want to battle. It's infuriating.