I'd prefer they didn't. Not adding the second analog makes FPS games not really practical and that's a good thing in a market over saturated with shooters.
Being that you can get every cookie cutter fps on one of the other 1500 devices out there, I rather enjoy the DS' unique non fps library unofficially enforced by its lack of a right analog stick.
Though I will take the additional buttons and large screen, oh an a mini HDMI output, or ability to reverse remote play through Wii U. That would be awesome.