Since the dawn of time, game demos have been a largely proactive experience. You hear about them, and you have to go out and get them yourself. Nintendo might have a better idea.
During a recent Q&A session with investors, company president Satoru Iwata said, "When Nintendo would like to ask users to try a specific new game, we should deliver it to their Nintendo 3DS, and possibly Wii U, with their prior consent and recommend that they just try it and, if they like it, they can pay for it. In this way, we need to introduce users to unknown products."
That sounds a lot like "sign up to a service and we'll beam you every demo we can". On the one hand, it might be a problem for markets with monthly bandwidth limits. On the other? Demos are a dying breed on other platforms, so if Nintendo wants to start championing them, that's something I am all for.