Pokemon on PC/360/PS3 would have different graphics, possibly better, yes. However, it would be 3D. Let's be honest, even the original Gameboy games looked better than XD/Collo, even though they were generations apart in graphical capabilities. Pokemon just isn't suited for 3D.
Also, Pokemon is a handheld game at heart. It's usually a small kinda thing for playing a bit on the road or when you're bored. You're never gonna get away with dumping it exactly as it is on a console and getting away with it. Colo, XD and the like are "spin-offs" for a reason. They're also pretty terrible (besides Mirror B.)
The internautical capabilities as they are on the DS are good enough. It's not necessary to have anything like scoreboard, achievements and the like. Plus, nobody wants to have angry 10-year old prepubescent little boys shouting expletives at the top of their lungs across the internet while playing Pokemon. Nintendo WFC is all we need for Pokemon battling; it doesn't require hardcore stuff. Anyway, Mario Kart and SSBB work fine with Nintendo WFC and Pokemon's system is far simpler.
No offense, but you sound like a little kid to whom graphics are everything. They aren't.