It'll all depend on where Nintendo goes with Wii2 I suppose. I agree, it'll likely get a lot more initial support than Wii did but if it's still too far removed from where 3rd parties are focused, they'll continue to concentrate on MS/Sony.
With 3DS it's an easier sell to 3rd parties because DS was such a monster and not only a hit with casual, but with many core titles on it from millions of JRPGs to GTA:CW to various shooters and action games. Plus, no one makes money making games for the PSP due to piracy so I can imagined they were all too happy to jump on the 3DS bandwagon.
It's also graphically on the same level as PSP/ipad/phone/pod (better really) making it possible for 3rd parties to make the same game for multiple systems.







