Sutch would have had an active fort had the city not been cancelled, the only clue to its existence in game being a dialogue error in the fighters guild and an old map. Bizarrely, the quest where a group of imperial legionaires ask you to defend the fort remains, despite the fact that it is now a ruin filled with marauders who would do a better job of defense than the legion anyway.
Serjo turns-the-page,
Sutch has been the topic of quite a bit of controversy in the past, mainly due to old maps of Cyrodiil showing Sutch as being a city, not just a simple fortress, but you have addressed this issue
supra. Additionally, I concur with your assessment of the "Sutch situation".
Fort Sutch appears to have been one of the few forts that was likely still operational and in use immediately prior to the Oblivion Crisis. Its appearance as being "ruined", I believe, is due to the scorching and other events that correspond with the daedric siege.
Nonetheless, we have no direct evidence of the aforementioned conclusion and must proceed based upon our logical progression and deduction, not upon objective "finish line viewing". But such is the weight of our endeavors, and may JHUNAL illuminate your searches, for I remain...
Yours in the Scrolls,
___The Word Merchant of Julianos