I don't think so:
"Much of what is written in this book is pieced together from documents captured from the enemy during the war, interrogation of prisoners, and eyewitness accounts from surviving soldiers and Imperial officers."
K, now read this.
"In 4E 174, the Thalmor leadership committed all available forces to the campaign in Cyrodiil, gambling on a decisive victory to end the war once and for all. During the spring, Aldmeri reinforcements gathered in southern Cyrodiil, and on 12th of Second Seed, they launched a massive assault on the Imperial City itself."
Now, there's no way survivors or eye witnesses could know the info in the second quote, so that means they HAD to have gotten the info DURING the war, as the book said they did, because that is the only time they'd have access to prisoners, and that's when they would have discovered their documents. This means the Empire KNEW how weak the Dominion was and they still caved.
Besides all that, what Imperials consider great tacticians is funny. He decided to fight instead of dying trapped in his city. Good, he has common sense. But if he was such a great tactician, he wouldn't have won the war and handed the Thalmor the prize money afterwards.