Two things will keep me from buying this game. (completely revamped this post)
If people can use game shark to level up and edit their Pokemon to max their attacks artificially that ruins online competition.
If this is not one step away from an MMO they have done something wrong. Pokemon needs to be online centered game. A mmo is too far, but the item trading, leveling, community need to be online in a big way.
Here's a suggestion. Make a pokemon university in the game. Your a student. So if there is something you need to know you go on field trips. Otherwise you can go exploring off campus. The main story can be 10 hours long to learn the HMs. While you can level up easily and practice battles at the university. While it also can be a hub for all your online battle needs until you reach high level battle which will be part of the post-elite battle system.
Edit: it's really obvious that I wrote this on a tablet, on bus, with autocorrect...