I consider myself a casual Trek fan, since I haven't spent any money on it, but watched the shows. I did like Enterprise, though I think they wasted a chance to show the origin of a lot of things and contact with different races. It could have been as good as TNG. Heck I didn't even like Scott Bakula until he was on Enterprise.
As far as the NX01 Enterprise looking too new, you couldn't backdate the show to make it look older than TOS. It would look cheap and crappy to all but the most diehard Trek fans. The original sets were good for the time TOS aired, but wouldn't work for a wider audience when Enterprise aired..