I think a large portion of the problem with both sides is that they’re based on assumptions rather than information. Basically, if you assume that the rumours are true (which they may not be), the rumours are so vague that they don’t tell us anything that can be used to say anything about the system.
First off, in terms of hardware we have been given vague information about what the components will be without any specifics that would imply how powerful this hardware is; and people are assuming its performance range to justify their biased opinion on whether the system will be successful or not. In many ways I think that this argument is (somewhat) irrelevant because how Nintendo intends to use the hardware is more important than the actual specifications are. After all, the visuals created by similar hardware when outputting graphics in 2D at 720p @ 30fps are significantly different than what can be produced in 3D at 1080p @60fps; and I’m more inclined to believe that Nintendo would focus on 2D at 720p @ 30fps.
Secondly, there is the controller which we know almost nothing about. Even if you assume that Nintendo has a controller with a touchscreen the implications of a device like this are largely based on people’s assumptions about it. If it is their standard primary controller it will have a different impact than if it is a standard alternate controller (see: Nunchuck) or if it is a game based add-on (see: Wii Fit). Secondly, and more importantly in my opinion, is how is Nintendo going to use it. If it is a touch screen for the sake of adding a touch screen it will have a different impact than if it was something Nintendo saw as essential; and even why Nintendo thought it was essential could have an impact, because Nintendo could see it as allowing people to have more undefined widgets in games, or it could be used to merge videogame playing and social networking, or it could even be used to allow people to play videogames without the need of a TV (possibly even introducing interactive TV).
Finally, I see lots of arguments about who people believe that Nintendo is targeting with this system primarily in hypocritical arguments. Even though they always argue that they own a Wii that is gathering dust many (so called) core-gamers argue that Nintendo couldn’t possibly attract their attention to buy a system; and (at the same time) in spite of Nintendo converting the casual audience from the Playstation people argue that Nintendo could never convince casual gamers to buy a new system because they already have something that is good enough.