Unfortunately, there hasn't been any solid evidence in-game to support the idea of them unmaking Mundus, but their desire to remove man from Tamriel is pretty obvious. It's reasonable to assume that this hatred of man is leading up to something metaphysical, such as the deactivation of Direnni Tower. Besides, it was MK, who gave Kuhlmann the idea for the Thalmor. Anywho, the only thing that we can say for certain is that they are trying to bring about a new Merethic Era.
False God! This is the end... the final turn of your Wheel!
Yes, as well as Brass Tower (Numidium). Snow Tower is the Throat of the World.
MK = Michael Kirkbride, former Bethesda dev. Wrote most of the lore (much of it very obscure).
If you don't know what 'Love Letter from the 5th Era' is, google it. I can't be bothered to explain the theory about the Towers, that Rebel guy might.
Aren't half the towers non-active now?
Numidium was deactivated in Daggerfall Red mountain by either the events of Morrowind or the Red Year, not sure which White Gold by the Oblivion Crisis
and I'm sure the events of Skyrim will impact the Throat of the World in some way causing it's deactivation.
So really the only ones still active are the crystal and adamantium towers so maybe they might decide where the next game takes place based on where the next tower is.
Crystal-Like-Law was taken down during the Oblivion Crisis by the Daedra. The only one that is for sure left active is Ur-Tower.
Numidium breaks time whenever it is activated, so whether it is still considered active is unknown since it was destroyed but is also active in the 5th(?) era. We don't know if the Khajiit actually are a Tower or not so that's also unknown (if they aren't then we don't know what their Tower is). Tree-Sap stopped moving, but it is unknown if it is deactivated or not. Snow Tower is sundered so that could mean something happened to it (or it could just be referring to the divided Skyrim, or both).
There are 1-5 Towers left.
http://tinyurl.com/aeadm3b A word to the wise ain't necessary - it's the stupid ones that need the advice. ~ Bill Cosby