Persoanlly, I wound up thinking early on that Enterprise was the early history of the DS9 Mirror Universe, since continuity'd been buggered so bad in that show:
Answer to "Broken Bow" Script: B.T.ABasicly, if the Romulans had a good cloak back then, they'd have owned the Humans in the subsequent war. At best I'd imagine they'd have good ECM, of which the writer's for "Minefield" could have used. Having the Romulan ship playing cat-n-mouse with a crippled Enterprise while trying to scrape Reed off of the hull might have made for an even more interesting episode.
I ran into a similar explanation for the use of green on Klingon/Rommie ships, although they described the effect as a "lasing" effect, not that different from the one posted here. Non-canon, of course, but the show has never given any explanation as to why both Empire's ships are all green...
Although the mention of 80 years in "The Neutral Zone" precedes the mention of the Tomed Incident (2311, or 53 years before TNZ, and an implied Fed involvement), there was still a Romulan ambasador standing in the Fed Prez's office ony 70 years prior to the ep. That, and a number of other references seem to imply that the 80 years may have been a miscalculation.