Legion does not have much in the way of actual named quests. However, I like to make up my own, and act as a frumentarri wrecking havoc secretly on the ncr.
In the wastes, I proudly wear my legion gear, but in ncr heavy settlements I often wear nice clothes with a hat. It is pretty fun playing this way, and there are quite a few examples where you can mess up the ncr in their own quests.
"King Koopa has never had level designers of this quality"- Super Mario Brothers Frustration pt. 1
The Legion doesn't have many quests because they're already operating at maximum capacity. If you think about it, quests are you solving someone else's problems. The NCR as said by many to be stretched too thin has a lot of problems. A lot of problems. So you can run around cleaning up after them because without you they fail hard, but the Legion doesn't need you quite so much. Their troops aren't incompetent like the Misfits. They don't have the people at the top sabotaging their operation (the Ranger leader) and so forth.
Even the ground-level troops seem to be in a state of defeat: "We won't go quietly." As in: "when we die, we'll take a few of those bastards with us."
The Courier singlehandedly wins Hoover Dam for the NCR, no question. Without him/her, the Legion would have taken the Dam.
Small consolation, but if you're roleplaying a Legion-loyalist, you've got a reason for the quests being disproportionate now.
Twilight: One woman's struggle to choose between necrophilia and bestiality. ~The Official King Caelum of the Versus XIII boards~