Among many titles coming out this year that I'm excited about, only recently with various trusted impressions and previews (see opposable thumbs, gamereactor and video games daily) has Super Mario Galaxy 2 sprung above the cloud of anticipated titles this year. I can tell you right now part of this has to do with the elimination of the hub world. That's an irritation I had in the original straight up, not initially but once I was up to getting the 60th star, I was kinda getting shitty at having to go from one side of Rosa's mothership to the other just to get to the next level was tedious as shit. The other improvement is the elimination of narrative and I mean no offense to Yoshiaki Koizumi (like he would give a fuck anyway) but I did not give two shits about Rosa and her star bit crew, I personally would like to see Koizumi work on the next The Legend of Zelda game as I think he's got a lot of grand ideas that would better suit that franchise than Mario itself. Thirdly, the implementation of Yoshi and the new abilities both Mario and Yoshi can exploit have this game recognizing it's strengths and weakness in one master stroke.
Sometimes implementing new features in an established franchise isn't always as transcendent as they intend to be and quite frankly, it has taken Nintendo 11 years to truly gather it's chips and return to it's former glory that had everyone in awe. If Super Mario Galaxy was the step Nintendo took to return to the path of creative integrity, then Super Mario Galaxy 2 is looking to refine that integrity and craft the next best installment to the Mario franchise. It's also good to see Nintendo return to their former design philosophies in trial and error as well; there should never have to be one Mario title per generation.