Instigator said:you're welcome to prove me wrong, junior member.
There are a few games out, and more in the work, that put the dual screens to good use. Wario Ware Twisted being a great example of the former, and Romance of the Three Kingdoms DS, the latter.
Kirby's dual screen usage is pretty handy, and Castlevania and 2D Metroid will also make great use of it. Not sure if Metroid Pinball uses both screens to display the 2 halves of a larger pinball board, but if freakin' should, and that too is a good thing. Sonic's implentation looks great too, your complaints aside.