Because after all, they are a duo of 3DS games. So what features/attacks/events/whatever are you looking forward to seeing in the three dimensions?
For example, I think something as basic as an egg hatching could look pretty neat with the egg shell flying off the screen (Similar to whenever you collect a Pokemon in Super Pokemon Rumble).
Oh man the eggshell thing sounds cool and I bet they'll totally do it too.
I'm expecting skyscrapers or tall buildings/trees to poke out of the screen, maybe a layer of fog too.
It'd be cool if attacks like Water Gun had some droplets of water flying out of the screen.
Razor Leaf. Those leaves man, coming right at you.
And Fire Blast
Shadow Ball. In every game Shadow Ball has been flat and disappointing. But now... Plus I'd like to see the new cutscenes/special angles they can come up now that they experimented with that in B/W with Skyarrow Bridge.