@Mr. Khan  his name is Mario, thats why. Anything with mario is almost sure to sell big, people just find 2d Mario more accesible than 3d, which i agree with but Sonic is no Mario, hasnt been for years. Look at all the non Nintendo platformers, do they sell millions??? Hell no. (except for LBP)

Sonic has absolutely no sales issues. The trick to making Sonic sell loads has also been shown: couple him with Mario.

Mario & Sonic @ The Olympics sold 12.64 million. Just to clarify, that's more than Sonic 1, 2 and 3 combined. 

And the non-Mario installments are still huge successes. Across all platforms, Sonic Unleashed sold 3.93 million. For a comparison, that's more than Uncharted: Drake's Fortune. Sonic Rush sold over 3 million too.

While you can debate Sonic's recent quality, his sales are still quite amazing.  His games have sold around 43 million so far this generation. Grand Theft Auto sold somewhere around 54 million on consoles last generation. Sonic is poised to beat that.

Sonic isn't anywhere near Mario (180m this gen) sales wise, but it never was. It's roughly as large compared to Mario as it always has been. Which, all things considered, is pretty brilliant.

I believe Sonic is either in the top 10 best selling franchises of the generation, or close to.

It's not quite the same, since it's hard to make the text look right, but here's the idea:

after looking at the sales of the original M&S games, I've just noticed something interesting.  For both the Wii and the DS version, over half of the sales come from EMEAA.  On the other hand, for the winter olympics sequel, EMEAA sales are only slightly above that of NA.  There was a large drop off in PAL sales (over 2m compared to NA's under 1m).  I guess it could be said that the sales of any sonic game are somewhat highly determined by success in EMEAA.

What's even more interesting is the fact that despite the lead SEGA had over Nintendo in 4th gen Europe, Sonic sold much worse in Europe compared to America.  However, this gen the likes of Sonic Rush sold more in EMEAA than in NA.  Basically, whatever SEGA has done in recent years with Sonic in PAL territories actually seems to be working.

Plus, M&S in London is probably going to sell really well here too, probably due to a mixture of a weird type of patriotism, love for the series and the infamy of the title characters.

I don't believe that. I think if it's a good platformer it doesn't matter who's on the cover of it; it's sell. Maybe generations won't be that platformer but I don't really think mascots mean as much as companies made them out to be when it comes to selling games.

The only thing I believe would hinder a good Sonic platformer would be the series' tarnished reputation. It could be at the point of no return now. Regardless, SEGA isn't helping by continuingly putting out spinoff titles like this.

The gameplay.

I meant the picture

Yeah, I was this close to suggesting it be called The Real Sonic The Hedgehog 4. Specking of levels platforming games have really seem to have taking dive in terms of level design since the NES. The Sonic series itself seems very tame when compared to the likes of Super Mario Bros., Ninja Gaiden, Castlevainia. I just can't quite put my finger on it as to why that is. 

@IamAwsome

Um, I don't know what you're... I think you're taking the picture too literally.

It's just supposed to mean they'd take out the "Modern Sonic" portion of the game.