I want to see Mighty No. 9 surpass Rockman as a franchise in general, it has all the structure there to improve on the gameplay and add another layer of depth to the design.
Best example are the way his powers are made, powers in Megaman are for the most part unneeded fluff that don't change the way you play and just give the option of dispatching bosses faster, however Beck's forms will actually be used to solve stages, change his very mechanics, giving a real different feeling how to go about clearing a stage. Sure there were a few things like freezing the lasers in Quickman's stage, but these kind of things are very sparse.
When a boss is defeated by these new forms, I want to feel like "Oh that makes sense, I pulled off his shield with one form, and smashed his weak point with the hammer form" rather than "Alien Wily is weak to bubbles, I dunno"
These are some of the real reasons I'm excited for MN9, its both what made the games of old good but with the evolution of new, and modern graphical power.