Splatoon is everything about how to do a new IP right. A great blend of new and old, great marketing, a clear target market (that happens to heavily coincide with the Wii U's userbase), a very high quality game, and great support after launch keeping brand positivity and freshness.
Hopefully Spla2n - when it comes - will be able to build on this momentum and make Splatoon one of Nintendo's A-list franchises.