Before I go anywhere into this section, PLEASE stop telling people that Brolli is the Legendary Super Saiyan. He isn't! I have many points and facts to prove that he is not the Legendary Super Saiyan.
First, Brolli only appears in the movies. Movies have nothing to do with the show. Second, he only reaches up to the Ultra Super Saiyan stage. Every saiyan Z Fighter reaches that stage. There is nothing special about it. Who do I think is the Legendary Super Saiyan? Simple, and true. Goku...Goku is the legendary Super Saiyan. Why?
Goku is the first one to turn into a Super Saiyan in the show. But, that's not all. No, Super Saiyan is not the legendary stage. Think about it. Goku is the only character in the show to reach the Super Saiyan 4 stage (the true way..Vegeta cheats)...This stage has NO Super Saiyan characteristics at all. It is a totally new stage. Although I can not truely tell you that this is a fact, I believe that the Super Saiyan 4 stage is the Legendary Super Saiyan Stage.
One last point I have to make. The entire show is about Goku. Dragonball, Dragonball Z, and Dragonball GT focus on Goku. He reaches Super Saiyan first. Then he is the only one to reach both Super Saiyan 3, and Super Saiyan 4 (and stop thinking Vegeta actually achieved this stage..he didn't). If you are going to make a show about someone, then you are probably going to make them the "legendary" one.
So..to end it...Brolli = NOT LEGENDARY SUPER SAIYAN......Goku= LEGENDARY SUPER SAIYAN...the only other person I could say might be the legendary Super Saiyan, is Gohan. I would probably say that he was, but he is a Mixed Blood Saiyan. I don't think someone who is half Human would be a Legendary Saiyan...