I think the problem with Mario is that, unlike Sonic, Mushroom Kingdom is very very iconic. You can't mix up the enemies and environments too much, or it loses that Mario charm. This leads to a lot of the titles to being very samey and lacking of originality. At least in terms of visuals. They do mix it up gameplay-wise, but again if they do it too much it becomes something other than Mario. Like, Super Mario Sunshine is a fun game, but that water mechanic just ain't Mario. Thankfully, unlike Sonic who mixes it up TOO much (at least from 2004-2008), Mario has rarely diverted from the basic gameplay mechanics. Galaxy 1&2 are great games, but again, I think they divert too much from the formula. I got tired of running about on spheres and navigating the hub world. Also, I didn't like waving the Wiimote at the screen to collect items. I really just wanted a flat surface and a standard controller.
Which is why I like 3D Land so much. Its the best marriage of 2D and 3D Mario I've ever seen. I think being on a handheld title helps, because they try not to go too big with the environments and keep things restrained to a linear path.
I will say that I really appreciate how Sonic Team handles callback to the Genesis originals. I mean, look at Mario. A callback to the NES days happens all the time. Mario fans LOVE their nostalgia and Nintendo loves giving them what they want. But I think this over saturates things and makes it less special to see a reference to the 80's games.
Sonic, Meanwhile, has just started this trend but is quite reserved about it. Sonic 4 and Generations were the only titles to really go all out in the homages. But Colors, I think, did it perfectly. It was awesome encountering an old badnik in a new setting. Like the massive Motobug in Starlight Carnival. That was great! I hope SEGA keeps these homages and callbacks coming, but not at the Mario scale so they continue to be special.
