Yep, after many quests it does seem that the choice of legendary traits is random. The good news is you can save right before you do the last step that will reward the legendary trait and always exit to the main menu without saving if the trait you want doesn't appear in your list of choices.
In other news, I've been drooling over the Guild Connections trait just because I love to dress my sims and decorate their homes. I got it for my merchant, who then became the monarch of my new kingdom and, I have to say, the discount on furnishings is quite nice as is the ability to access every outfit for your hero's gender. I know it's a complete throw away LT, but if you like a lot of new shinies when you play it is a fun one to choose.