Of course it's not stronger than when it first went to war, but the AD is also weakened, likely even more weakened that the Empire is. The AD was succesful at first thanks to the element of suprise.
The Nords have little right to complain, they lost one of their gods wich isn't an Aedra for a few years. The Imperials lost their home, and did by far most of the fighting, and lost the most troops. As well as their capital pillaged, along with many other major cities.
The Imperials took 5 arrows to the chest, the Nords got stepped on their toe. And yet the Nords do nothing but complain and rebel and only make it easier for the AD. Should't be suprising, them being Nords and all.
Let us see on the historical fact in Earth.
No one Empire had rule this world more than 1.000 years (The record is 1600 years). The Roman Empire fall because of the internal contest. The Britain Empire fall because of the independence of regions. The Maya Empire fall because they were technological backwards.
I do not believe the Empire of Tamriel can ruler one era more
I actually helped create a Tamriel Total War mod, but it was never finished. The guy who led the project and many others of the original team left, I did too. But some other guys took over and continued it, I still have the old unit rosters in my documents.
I should check up on that project.