Liara had a personal involvement in the mission on Noveria, it was her mother you were trying to kill, after all. She didn't do much, but I believe that there was some extra dialogue if you brought Liara along on your team.
I was just thinking exactly that. Indeed, I think she was the only one with an actual personal stake in the events. Everyone else had their reasons for joining up of course, but Liara was the only one with a personal connection.
Still, the mission wasn't really about
Liara and her mother, not like say Jacob's loyalty mission was about him and his father. It was about a Rachni infestation and Benezia just happened to be the end boss. I'm not saying Liara or any of the others didn't get any
character development at all, just that ME2 did a better job of fleshing out the characters.
The problem with Jacob is that he starts off being this fairly nice guy with an interesting backstory, then he practically becomes a different person once you get on the Normandy. His loyalty mission sucked too, since it didn't really affect his character in any way, was yet another family issues mission, and Jacob's backstory as a Corsair would've given us a pretty awesome mission.
You know I'd forgotten about the Corsair thing. That really could have made for a much more interesting mission.