I can't believe you people were seriously expecting a fully 3D Pokémon game for the DS -_- 3D graphics (unless they were really, really crappy) would fill up quite a big amount of the data allowed on a cartridge.
and seriously, are graphics everything that matter in a game? Do you think Nintendo should just throw away all the even slightly more complicated things (including some parts of the Pokémon battle system that make it so unique) in the game just so they could have fancier graphics? <.<
Try being realistic for a change, I doubt any of the people who sayed they're dissapointed because of the game being 2D understand how much space the complicated battle system, EVs, IVs, Breeding, etc. require.