Speaking of stars; on wind waker if you go to windset island highest point at night and pull the telescope you'll notice the stars are 3D and they actually animate; they spent resources on something like that (in that sense it's more impressive than TP).
The clouds are also in volumetric 3D on WW, clearly noticeable in the day/night cycle changes.
Anyone want to point out some of the nice details I may have missed in Skyward Sword?
All this Zelda talk makes me sad that we won't see Wii U Zelda until about 5 years from now. 8[
I found SS to be technically not that ambitious.
It was happy with it's tech, not trying to fight his way out of it like Zelda TP was. There's lot's of details in there still, but the game is a lot more fragmented and self-contained, not just because of the level design meaning it that way. It kept most details (it's the same engine after all) like how link will look at people's faces automatically and the like, the wet clothing too, and it's the first Zelda to feature cutscene models that are way more detailed than the "in-gameplay" ones. Other than that, and some details that I'm sure are in that I am unaware of, it should be the zelda game that features less impressive easter eggs.
Even the water, the devs with TP developed various kinds of water, Goron Sauna kind of vaseline misty water, Lake Hylia having less effects because of the extent (and the fact you could dive) and of course fountain water with all the effects on top.
Zelda SS? One kind of water only. Technical prowess took the backseat there, other than messing with the graphical style, overhauling the level design structure and items it could be a "mod" of the existing tech; it pretty much used what was there already, the whole time traveling thing surely being based on the twilight and light world travel elements mixed with the way midna's attacks worked (the perimeter thing). Also the trials were clearly the goddess tears quests overhauled as well.