I would immediately cease the repetetive recycling of the "New" series. I argue it stands as the antethesis of everything that made the Mario franchise the former console seller that it was.
Nintendo has a game design principal in which they create a game around the control scheme. This sounds obvious, but plenty of companies start with a story idea or a theme. Nintendo starts with what feels right in your hand. This is generally a good practice as we've seen Nintendo's attempts at innovation over the many years often showcased through their Mario games.
This all came to an end after the first New Super Mario Bros. From then on, each game was more like an expansion pack of the first and little in the way of genuinely innovative level design or controller use has come along. One of the driving truths behind the Mario franchise is that each game is different fromt he last. Even on the same system, you have wildly different experiences even though you may be playing similar in game mechanics. The simple but finely tuned physics of the first gave way to the dream like cartoon scape of Super Mario 2, which then became the stage production play of Super Mario 3, which moved into the Dinosaur world of Super Mario World, etc etc. Each new game was a new experience.
To bring the franchise back to a higher degree of merit, the next title must not be another "New" Super Mario Brothers, and actually BE a new Super Mario Brothers, with all new themes, world designs, character models and ideally, radically redesigned move sets. It should thoroughly exhaust the potential of the Wii U's unique capabilities and showcase it's strengths.
