If Nintendo releases a new DS redesign it will probably be after the next gen handheld is released, and it will not have GBA support, just like the Game Boy Micro was released after the DS and had it's GB/C support removed. It will be smaller and cheaper, possibly with smaller screens. This is all conjecture of course.
When Nintendo releases a new handheld system I won't buy it if it's main selling point is a gimmick. I hate the touchscreen on the DS; for every game that uses it well there are 10 others that force you to use the touchscreen for no good reason, and 10 more that are based on bad touchscreen controls. I firmly believe that the DS would have more good games if it didn't have a touchscreen. I'm not going to be buying a Wii either, for pretty much the same reason.
I want game systems, not toys designed for toddlers and old ladies.