I think the current developer support has nothing to do with the specs, it was obvious that the next generation handheld would be more powerful (shame on Ninty if it didn't!), I think it has to do with 3 things:
1- the success of the current DS: the DS is about to become the console/handheld with more units sold (sorry PS2). Developers know that many people will jump ship to the 3DS once it launches and they don't want to miss a piece of the pie.
2- 3D: everything right now is 3D. Movies, games, pictures, etc. 3D is the new entertainment industry darling and developers know many people are eagerly awaiting an affordable, glasses free 3D experience.
3- The hype after the announcement: you know how it went after the 3DS announcement, press was really enthusiastic, fanboys were crying tears of joy and lots of people know about the existence of the handheld. Seems like many people are willing to hand over the cash to get one, and software is what makes a console (with exceptions like the Wii and it's lack of third party support).
Just my 2 cents.
