If Nintendo needs to do that in order to finally provide a quality online service on par with their competitors, I'd be okay with it.
Frankly, I'd love to see a Netflix-like service that gives my access to a large back catalog of Nintendo games for a fixed monthly price. Maybe cycle out games every few months, give people the option to buy currently available games at a discount so that you can keep playing after they cycle-out. Certain classic games should never cycle out, of course. If Nintendo wants to combine something like that with a high-quality online service and maybe an improved Miiverse, I'd be down with a monthly sub.