This may actually make porting PS Vita games to the 3ds faster. Since you won't have to chance the control much.
I'm betting however the original version of this device won't leave japan. Nintendo will ended up releasing a revision 3ds first and leave 3rd parties to make their own versions of the add-on. IMO the touchscreen should only be used for inventory, items, equipment ect and maps. I found many ds games frustrating with the touch screen mandatory used for actual control beyond maps/items for games. Nintendo is finally learning basic non-gimmicky controls are best. If they do the basic control route for the wii u, the 3ds may not be my last Nintendo system after all.