It seems that they have knowledge about the future but then it turns odd that they were surprised by the return of the Dragons. All this makes me to believe that everything is connected to the divine of time. This divine's one aspect, Akatosh was the protector of the Empire and his acts stopped the Oblivion Crisis. Well then his Nordic aspect Alduin returns to world and brings the other dragons with him. (Alduin is probably the reason why return of dragons was hidden by Aldmeri Dominion.) But there has been nothing about the elven aspect Auri-El. I think the reason is that the Dominion actually works with Auri-El and I believe his role is to be the protector of the Dominion as the Akatosh is the protector of Empire. Auri-El may be the key why Dominions timing is so perfect. Does this make any sense to you?
Yes it does, its a very interesting speculation.
Considering that the Thalmor's ultimate goal is to 'uncoil the Dragon' so they can 'regain the mantle of the imperishable spirit',
(They want to end the world by unbinding time and reach heaven by returning to Anu), and considering that their sense of timing is impeccable, it does seem logical that 'time is on their side'.
Consider their war with the Mede Empire.
They came to the Empire with demands. These demands were seen as ridiculous and led to war.
The war cost the Empire Hammerfell and led to the civil war in Skyrim.
At the end of the war the
exact demands the Thalmor made before the war were met.
You could say the war cost the Thalmor nothing and won them everything, the Empire would have been better off accepting the terms in the first place and avoid the war.
But the Thalmor knew they wouldnt.
Edit: About the Thalmor's potential for warfare:
They do not need to use their own as footsoldiers. Its possible that the Thalmor and Altmer themselves hang back and give orders, are the generals. The actual fighting quite possibly can be done by Imga, Goblins and Atronachs.