I really don't get the complaints about this game. It looks amazing, everyone who has played it says it plays brilliantly.
If this game came out with any other name, you'd be going on about how innovative it is, how nice it looks, how multiplayer 3D Mario is amazing.
I fail to see how it's attempting to get "casuals". Anybody who has played 3D Land will attest to that, it gets really tricky and is a fantastic game.
Yes, Nintendo could have made a Metroid game, or a Starfox game, or something to "win back" the core, except it wouldn't work. Those games barely make over 2 million sales, if they even manage to break 1 million.
Nintendo is a business and they need to do what is best for that business. Super Mario 3D Land spurred sales of the 3DS drastically, and its merge of 2D and 3D Mario games made it the fastest selling 3D Mario game to exist. It is what the Wii U needs. Bundle this with a Wii U for $300 around Black Friday, and the Wii U will fly off shelves.
They have implied that the music isn't done yet, and it will be orchestrated