Mario Galaxy has incredible graphics, so no need for a remake. Skyward Sword is a beauty but there are some graphics issues I've noticed some white edges and some blobs depending on the angle and distance to the element.
I highly agree with Joel, but I believe that there is a cost-efficient way of going about this (not the Halo Reach revamp of Halo way). If they can hire smaller teams (like Grezzo as Jumpin mentioned), not only is it a good exposure for these teams on key Nintendo franchise software, but it also keeps these peoples' skills busy on Nintendo projects, and allows Nintendo to keep pumping out their regular content while offering even more. MORE IS BETTER. Period. While they do this, they need to keep expanding and have people also work on high-profile 2D software and casual software, as well as their 3D software.
I think as long as they don't neglect their non-remake content, nobody should complain that Nintendo offers more. You don't want it? Then don't buy it, that's my opinion. Now if Ninty only releases remakes that's a different story but I doubt that'll happen.