Personally, I much prefer the ambivalence and ambiguity in the relationship that we were left with... To my mind, that's one of the subtleties that make DS stand apart from most TV shows. The predicatable thing would have been to have them fall in love, and then there would have been a "Rhoda" style wedding (reference to the 1970s for those who remember!). I say, thank goodness DS didn't fall into that formulaic, cliched trap, but rather left things as unsettled as real life often is.
Am SO with you on this, Vlad. And I don't think it would have worked to actually have Barnabas and Julia get together. IMHO, it would have been most interesting if they'd have (mostly)avoided the Roxanne thing and featured further ambiguous interaction between Barnabas and Julia ala the "Not without you, never without you" scene we saw in 1995.
To give just a little of this, leaving us the audience (as well as the character of Julia), wondering and wanting more would have been just the ticket. Sort of a sustained foreplay...