I do wish the Romulans had been the big bads from jump. I think it would've had more impact seeing them foster dissension instead of Future Guy and the Suliban. Or even if the Romulans used the Suliban, Orions, or others, that would've been cooler too and made it easier to keep Earth from finding out the Romulans true identity.
I also wish that we had gotten a Romulan War on Enterprise. If not taking up a season or several, then doing it in a TV movie or a straight to video movie.
I don't get why Berman seemed to misjudge the audience's interest in the Romulans. At least this one audience member.
I would've rather had them than the Klingons. Plus Enterprise could've been the show that fleshed out Romulan culture in ways that TNG/DS9/VOY also developed the Klingons. Ah, what could have been.