Too bad that it would violate continuity--and completely ruin the 1966 ep-- to have them show up on "enterprise."
As for the movies, I've seen them all, it's the ONLY movie I'll go to on the first weekend, and I thought Nemisis was great. Namely because it highlighted the best actor of that cast, (apologies to Patrick Stewart), Brent Spiner.
Of the original series, how many episodes included Klingons? How many included Romulans? And how many other episodes had repeat races or characters?
Your suggestion points to exactly what has gone wrong with Star Trek. The first series was written by real TV writers and real science fiction authors who weren't copying anything else and who did their own thing. New planets. New aliens. Exotic and thought provoking situations that often didn't take the easy way out.
The later Treks have been written by fanboys (and fangirls) who can think of nothing original and only want to go back and have another Klingon episode, another Romulan episode, another Borg episode. The ratings are down? What alien or character from a past series can we dig up this week?
Why was there a Tholian in last week's episode? Some fanboy or fangirl writer couldn't help themselves. And what makes it all the more painful is that each "nod" to the original series only damages the continuity of the original series.
Zephram Cochrain was from Alpha Centauri and he certainly wasn't a hippy as portrayed in the original series. The Romulans and even the Ferengi were supposed to be mysterious and new aliens when they first appeared but how many times will we get to see them in Enterprise? How about seeking out some new life and new civilizations and boldly going where no man has gone before instead of seeking out well known life, well known civilizations, and boldly puttering around a well known and populated galaxy where everyone, except perhaps humans during the time Enterprise takes place, have been before.
The other thing that annoys me is that the Federation of the original series was on top. Now we're stuck with post-Vietnam anti-Americanism that has Enterprise flying around as the weaklings of the galaxy with the humans patronized by just about everyone as if they were infants taking their first steps. Original Trek had a few episodes where we ran into races far superior to humans. In Enterprise, it's an event if the species du jour is less powerful than humans.
As for the suggestion in the article that the crew be more human and have more problems, please no. Have them act more compitent and military. They already act like the rejects sent out into space because no one would want them on Earth. There is a reason why people reacted well to Troi being told to put on a uniform and that costume change stayed. This is a quasi-military ship representing a government, not the Love Boat in space.
Good suggestion, and maybe, just maybe, quit making the Vulcans the enemy. What's up with that?