I don't know if Nintendo will do this, but I've said for quite some time that they should. In another 2 years cartridge or SD-style memory will be cheaper and bigger still, and digital download will be increasingly popular. Years ago, a system was "mature" if it could play CDs or later DVDs in addition to games. Now the optical disc is becoming dated.
There are several advantages to switching to cartridges, and they go beyond fast load times, expandable memory, locally saved games, late-gen on-cart system upgrades and anti-piracy measures. The system itself could greatly benefit in terms of reliability, power consumption and form-factor. The optical drive is now one of the biggest single components in a console, and it's a moving part. Take that out and a system the size of Wii U could easily have an internal hard drive. This cuts down on manufacturing, shipping, storage costs and can help with system cooling.
Plus, discs are boring now. A new style of cartridge would be at once retro and new, and the kids would think it's cool. They're also tougher for the little ones.
Do it up, Nintendo!
