GameTrailers' use the 7-10 scale though and they spend half of the review saying it felt uninspired and unoriginal. It's most likely a good game, but I'm not sure the average customer needs four New Super Mario Bros. games.
I agree with that, I was actually expecting a 6-7 based on what they were saying (although it got more positive towards the end.) I'm happy full co-op is included, even if it is only two player and does require two carts. I think that's an important part of the NSMB series going forward and a key differentiator to other old-school-ish platformers and old Mario games, for that matter.
I don't think the issue is the total sum, on the contrary I think it's pretty cool we're getting a handful of modernized 2D Mario platformers.
But the timing is seriously off. SM3DL for 3DS came out last year, NSMB U later this year. NSMB2 should be next year at the absolute earliest, if not 2014, if they want to avoid brand fatigue. But to Nintendo right now, I can see why they'd choose to pump the 3DS up with all they got over concerns of brand fatigue. They'll have to deal with the consequences both ways (boosted 3DS sales at the cost of people getting a bit tired of Mario.)
It also weakens the Wii U launch by diluting the "specialness" of 2D Mario, especially since they're probably three months apart from eachother.
I think a new 3DS Zelda title would have been a much better option, maybe not for sales but if they timed it with the XL launch I think it would have done really well regardless.
Not much use complaining now, it is what it is. We're getting three Mario platformers in the span of a single year. The market will decide if that's too much, but I wouldn't really complain if Nintendo let the old guy rest a bit (and this coming from a self-confessed Ninthing, so that should say something.) I don't mind a new game in a Nintendo series every two years, one year is a bit close to Activision's milking but still tolerable. Once a gen like Kart and Brawl are what I personally prefer. Three in a year is just too much, but again, I understand why they're doing it.