Share when you're comfortable.
Well, for starters, I disagree with some of the stuff in the Cosmology text. In particular, I suspect that the stars and moons look the same to the Daedra as they do to mortals. If there is anything that can be attributed to "mortal mental stress" it would be the perception of distances to the stars and the sizes of the planes to be "infinite", as they're of such great distance and sizes, respectively, that it might as well be, for all intents and purpose, be considered infinite, even if the distance is technically finite. Such could also be seen in real life, as even real life technology doesn't even come close to moving planets or traveling to and from the stars. But as the stars can be perceived even from their great distance and the planes can be represented as finite bodies, they are not truly infinite but so vast that for all intents and purposes, it doesn't really matter.
Edit: It might also be the fact that Nirn seems flat, especially to a civilization that only rarely ventures beyond their own continent, so it is understandable that it seems like nothing more than "mortal mental stress" that all the bodies observed in the sky are spherical.
That's thinking within the "physical" box. With magic, you can teleport, or fly if you feel like taking the scenic route and don't mind being chased by every Cliff Racer in Morrowind.
As for the Animunculi, their construction was not only of the physical, but of the metaphysical as well. Machines, but enchanted machines. You shouldn't be surprised - take a look at the Tools, and the enchantments Kagrenac placed on the Heart of Lorkhan; though they didn't have a use for regular magic, but they were still very well versed in the metaphysical and used enchantments. There was more than just steam behind their functioning.
True, the Animunculi are both physical and metaphysical, as are all of the Dwemer's great achievements. Hence why the Telvanni seem to have a knack for them, because it seems that enchanting is an important factor with them. And there are plenty of Dwemer Animunculi, finding replacement parts and rebuilding them isn't hard. But I have interest in their steam-powered bodies, as well as the steam-powered machinery that can be found in a Dwemer ruin, and what implications those could have, and even more so if it's augmented by magical means.
As for magic, it can make individual travel instantaneous, but it hasn't eliminated other forms of travel, not by a long shot. It may be that the mages have limits to how much they can teleport at a time. Travel by road and by wind-powered ship are still the major forms of moving supplies and trade goods.