What if this actually really is the DS2, which means that there is no DS2?
This might sound strange, and I don't know whether or not it's feasible, but what about this: Instead of releasing a completely new generation of systems every few years, which is basically a new deal and could result in a loss of market leadership, Nintendo only releases revisions every so often. Some of these revisions are not only cosmetic, but encompass actual hardware upgrades as well. Not a redesign, just upgrades - slightly more powerful, a few additional features, but still binary compatible. They'd encourage developers to actually use that additional horsepower, but won't allow them to require it. Every new DS game should offer improved graphics on the latest hardware revision, but still has to run on the standard DS. Basically similar to how PC development works, the DS becomes the "minimum spec", the DS2 would be the "recommended spec".