I'm glad that J/C never took off during the show. Relationships with subordinates aren't a good idea, and probably forbidden by some Starfleet regulations.
Well, the superior officers are supposed to show the example, especially a capitain and/or a 1st officer. So yes, relationships with subordinates aren't a good idea and furthermore, forbidden.
(If Chakotay had been a civil member, well it would have been possible even If it made such a cliché!, but frankly, don't you think that Janeway and her 1st officer had hands enough occupied between the conflicts with ennemies to be managed and the missions of explorations to think to a romance or simply sex?! Well, ok, Paris & Torres made it very often and in the end, it ended in Miral's birth but, they didn't have to manage a vessel of 150 people!

).
I, just like most people, really disliked C/7. I feel Seven's first romantic relationship should have been with the Doctor, and very short-lived. Janeway helped Seven explore her moral self, but the Doctor was her social mentor.
Well, it seemed to me that Seven wasn't emotionally ready for romance yet (come on, she's a child in adult's body who keeps learning every day on herself and on the world which surrounds her, including social rules). So, whoever she chooses as a first romantic relationship, it would be a shot-lived romance which would have of strong chance to end badly, simply because expectations from both parts would be too different.
And I imagine her very well, to contact very regularly Janeway and The Doctor, her two mentors to have explanations.
Given that the Doc obviously held feelings for her, and his propensity for losing his objectivity sometimes, it makes sense that he'd allow her to pursue a relationship, at least initially.
The Doctor holds feelings for Seven, it's a fact but up to there, he knows that this attraction is one-sided (and besides, if you remember well, she made him understand it quite early and on several occasions during their journey on Voyager), what won't prevent him from fantasizing over her body of course, but it will go never far, too aware that any vague desires from him to want more, would have grave consequences on the special bond they managed to form through their years on Voyager.
(Seriously, the only people with whom Doctor maintains a special relationships are Janeway and Seven. And I don't think that he would be ready to waste all this for a moment of madness).
About Chakotay/7, the worst possible pairing, I'm just curious to see if it will be made a reference to this romance in Star Trek Renegades... .