Face it: Nintendo are not going to change the concept of the game a lot. 3D might be possible, but look at their franchises.
The legend of Zelda: Still saving the Princess.
Super Mario Plat: Still saving the Princess
Those are the 3 biggest Nintendo franchises (Sorry DK, but lately...) and Nintendo knows their formula's sell. They tried changing it, but that didn't work out. Not only for Pokemon, Majora's Mask for instance.
I haven't played Diamond/Pearl yet (I'm getting it soon though), but they have been doing slight changes all the time - that's more what they'll continue with. Maybe we'll see 6 attacks soon. We've seen 2 vs 2 pokemon, maybe that will become more common, we might even start seeing a couple of combos.
And hey, not all people chose the legendary Pokemons. If they do that, it is what THEY want, nobody forces them too. I, for one, almost never evolve my pokemon (I like them much better as young)
http://www.vgchartz.com/games/userreviewdisp.php?id=261
That is VGChartz LONGEST review. And it's NOT Cute Kitten DS
