There are enough games that justify the DS touch screen. There are none that justify two small screens versus one large one.
I actually adore map screens. Having access to a minimap and having to pause to see the big map is a pet peeve of mine. I'm just lazy like that.
edit: There's also the fact that Nintendo realised during r&d of the ds that sometimes a game would require the input be divorced from the output. That is to say, a game might benefit from a touch interface but not necessarily on top of the onscreen action. Kinda like how alot of iphone games suck because your fingers end up obscuring what's happening.
but that is a choice on the iphone, PSP, etc. They could easily split the screen in two, have one be a large mini-map and the other the action. This is the old Dynasty Warrior game for PSP:
You have the action on the left, the "second screen" info and shit on the right. You rarely see that because most games don't try and sacrifice the action view for information.
Problem with two screens is that if you decide to have one large screen to show all the action, it sucks. Contra 4, Yoshi Island 2, whatever. All have a giant gap in the middle and either ignore it or try pretend like there is unseen territory there. TWEWY is the only game where it was alright because it shows two different actions, and again, that would be just as good on one large screen.
The 3DS is the first time two screens at least made some sense. Nintendo was either too cheap or the tech wasn't there to have a 3D touch screen, so the bottom is the touch screen, the top is the 3D screen. I've been lost as to why people liked it on the original DS for the past couple years.
