Besides that, where else can Nintendo go from here? Nintendo needed a powerful marketing campaign in order to win over the casual/mainstream/non-gamer/whatever-you-want-to-call-them audience, and now that they have established their brand amongst them, they no longer need to focus so much attention on them. The 3DS shows Nintendo is trying their best to strike a balance between "casual" and "hardcore," and by the looks of it, it has already succeeded. And they will do the same for their next system. One obvious thing they could include for the "hardcore" crowd is a good online interface, which may actually not be so foreign to the "casual" crowd if done right, seeing all the online card games people play on Yahoo.
Plus, considering all the success and profit Nintendo just made, they can sink plenty of money into their next system because it's practically guaranteed to sell.