Friend of mine pointed out that, when he went to buy FF9 (released for the PS1 three months AFTER the PS2 was released), he picked up a PS2 at the same time instead of a PS1 because it just made more sense to buy a console that isn't technically "dying", especially when backwards compatibility won't be an issue.
Nintendo will play this same angle and it's a good one to play. Launch titles are NEVER going to be as strong as the titles released later in the console's life span so you might as well put out a good title with backwards compatibility to push the new console, especially if it has Rev features (which it very likely will).
As for the argument that Nintendo needs to "showcase the remote", I don't think it'll be a problem (it'll happen anyway), as the DS's features weren't truly explored until later in the console's life anyway and now there are plenty of games which would not be possible without a stylus.