I think DK:TF actually took a significant amount of effort. It's quite beautiful and the changing camera angles mean that the worlds really had to be full rendered in 3D. It's just a litte boring, concept-wise.
I think that's the real gripe with Nintendo at the moment. It's not that the games aren't good, just not all that original or ground-breaking. Mario3DW is every bit as nice looking as Galaxy, it just has a locked camera (though you can free camera as well) and no space backgrounds or flipping gravity. But it's also more retro and less fresh. Compared to the Wii launch with Wii Sports which was something completely new, and Mario Galaxy that was like watching nothing else, the roster feels a bit stale.
I don't think the games are lazy effort-wise, but you can make the argument that NSMBU, NL, DK:TF, Z:WWHD and SM3DW are all direct sequels to previous efforts without a big change in theme or style. So you could say that Nintendo is being creatively lazy. Even the title most people are happy about, MK8, is still a sequel.
I actually think SM3DW is pretty creative when compared to Galaxy in terms of gameplay. It brings the polish of 2D gameplay into the 3D world. Multiplayer is a huge step forward. But it is essentially lacking in a theme or "story" from what we have seen so far. And its similarity to the 3DS game really makes it seem like a step backward.
