"There were a lot of feelings, but nothing ever happened," she observed. "Either make it a relationship or don't, but you can't walk this line forever."
This seems to be under Coto's watch as well and was said at the end of Enterprise in season 4.
Well Blalock was right, that
"will they, won't they" BS became tedious, bordering ridiculous. Coto mishandled the romance badly IMHO, in spite of having good intentions (sound familiar?).
It might not be fair to lay the Season 4 treatment of T/T solely at Coto's feet. Berman and Braga, as exec producers, still had final approval of episode content and scripts. It's quite possible UPN had its mitts in there as well.
It's also possible that Coto et al had something else in mind for the Season 4 T/T arc (based on the groundwork laid in Season 3, especially "Similitude," "The Forgotten", "E2," "Countdown," and "Zero Hour"), but another objective took precedence (i.e., trying to increase viewership, esp. with the desired demographic, with more TOS-connected stories, more action-oriented plots, notable guest stars, 2- and 3-episode arcs).
"Home" struck me as a calculated move to put the T/T relationship on hold, which seems inconsistent with the Season 3 arc. My guess is that TPTB didn't have "Home" in mind during Season 3, but something changed after the renewal for Season 4. Perhaps UPN asked for a change in the tone/direction of the show as a whole; the network had exercised influence over story content in the past. And after "Home," whatever plans might have been floated for T/T had to get ditched, and the writers had to work from "Home" onward.
When Koss took himself out of the mix in "Kir'Shara," in as contrived a fashion as he was inserted into the storyline in "Home," I thought the T/T storyline would be picked up again, now that the T'Plot Device was out of the way. Instead, "Daedalus" and T'Pol's pushing Traip away (out of character, IMHO, based on the events of "Home"), appeared to be another contrived effort to keep it on the back burner. Trip's decision to leave
Enterprise in "The Aenar" because of profoundly self-oriented reasons (also seemed OOC to me) struck me as another contrivance.
It seemed to me that dangling plot threads from Season 3, such as Archer's psychological recovery from the Xindi war and T/T's relationship, were truncated or pushed aside, because there simply wasn't enough time to do everything. I understand "Home" was supposed to be a two-part episode, but it was pushed back to one, likely to make room for the aforementioned higher-objective stuff. And the season itself was cut from 24 episodes to 22: two less episodes to work with.
I remember reading in one or more interviews that Trinneer went to Coto at some point during the first half of Season 4 to express his dissatisfaction with the indecisions regarding the T/T relationship, and Coto told him he had an idea (the bond) that would move things forward. There was enough time to set up the bond in "Affliction/Divergence" before revealing it in "Bound," but with so little of the season left, and two episodes devoted to the pricey "IaMD," not much could be done with it afterward.
Regarding T/T, perhaps Coto et al were hoping that a miracle would come to pass, and the show would get a Season 5, so the derailed T/T storyline could get back on track. I believe Coto said in an interview that he would be working the T/T relationship in Season 5. But as Season 4 progressed, and the ratings didn't improve, the only pragmatic conclusion to be made was that S4 was the swan song of the series. People have posted here that "Demons"/"Terra Prime" was initially planned as a three-part arc, but scaled back to make room for TATV. One wonders if Coto had a very different ending in mind for Season 4--capitalizing on the bond, and T/T coming together in the wake of the baby Elizabeth storyline--to set up the Season 5 that never came to be.
Sure, a lot of this is speculation on my part. But looking at the state of T/T at the end of Season 3, and the jarring derailments of Season 4, I do think that a monkey wrench was thrown into the original plans for the season, and Coto and his staff likely did what they could with what they had. Any writer worth his salt would not have deliberately planned the overall T/T arc of Season 4 that we saw; a solid, effective, and satisfying structure organic to Season 3 just wasn't there.
The House of Tucker BBS kept very close track of interviews, rumors, and story developments during Season 4; someone who had the time to research the 2004-2005 threads there could, I'm sure, come up with sources for all of this stuff.
My .02
) something or other about somesuch, and no wonder this other thing turned out the way it did! 
There's no there there.
