It isn't just the Dick/Babs fans that dislike it. I think Jason fans dislike it because it keeps putting Jason in Dick's shadow. It's a tried story that Jason can't seem to grow out of. Give him his own love interests and friends. No need to constantly take from Dick's history to fill out Jason's character more. It causes needless drama. It is like Dick dating Catwoman, Bruce dating Lois, or even Jason dating Stephanie.
I mean I still think that him and Julia Pennyworth would be interesting. It gives him his own love interest within the Batman family, like all the other prominent Batman family members, and it helps establish her character and gives he some more roots to stick around longer. Plus I always thought the Alfred/Jason dynamic is interesting. As for Barbara I think people liked the idea of her and Ted Kord back in the day, but too bad that didn't go anywhere.