But the story is very, very different and stands out among all of them. I would say more resources was spend on it as well.
This was my exact thought when I saw Agent class story on Quesh. I hate that planet, main storyline seems unfinished, none of quests there ever gave any affection to any companion I tried, so I always assumed it was just extra thrown in planet. Especially since all class quests there were so bland. "Oh hey, we've just heard there is something/someone you have to do/rescue/kill on Quesh, go get it, and we will never mention it again". Trooper? "We didn't manage to pull out this team in time, yo go do it" Smuggler? "Some guys sent SOS, go at them" For almost all classes you could remove Quesh quest and story wouldn't suffer at all(OK, I think SW had pretty impactfull q here, but it also could be done anywhere, no special link to planet at all). But Agent is only class that can't go on without that quest, and that quest has real reasons to happen on quesh.
So it seems quit likely that this whole planet was created primarly for his storyline.
Oh, and Scorpio alone would be enough to win the competition of "best crew" in the game.
This is another thing that pisses me off in other classes. Multitude of companions that are here because they have nothing better to do, or simply because they are military and were assigned here, but aside from that have absolutely no reason to be here. Pierce and Broonamrk. Akavari. Doc and Rusk. Andronikos. Skadge. Both 'soldiers' on Consular. Even if Vector links are pretty weak he's somewhat used in story outside his planet, and you actually have reson to accept Temple. It's not only agent that has it 'good', Trooper crew also all has reason to be here, maybe even better reasons. But fact that Agent has hsi whole crew reasonably involved in his story is another piece of "got more work done on it"
It's not that other classes are bad, but when you see how much better they could have been, yeah. Not nice.