The problem with the TCW was the fact that it really could have been its very own series. I think that was a real problem the writers had. They had two very good premises--a prequel and a time war--both of which deserved their own series yet the writers tried to shoehorn both into ENT.Which I had a problem with - a more developed myth arc about what the cold war is, who the factions are, what their agendas are, and so on, would have really made ENT's rather haphazard pre-S4 attempts at story arc more worthwhile.
By really fleshing out the players, their agendas etc the writers would have begun displacing the prequel element to the series and the need for our crew. We saw many times where the writers had to make less than believable logical acrobatics in order to maintain Archer et al as our protagonists instead of Daniels. Also there was a segment of the fanbase that tuned into ENT to see a true prequel and the last thing they would want is to witness corrupted events set in motion by forces from the future.
The TCW and the Xindi arc really in a lot of ways were forebearers of the type of complicated storytelling style that shows like Lost and Heroes use these days--lots of vague motives, dubious players, more questions than answers, answers only spawning more questions, ambiguous actions etc.
re: Future Tense.
I thought it was a solid high concept mystery episodes TNG did quite well.