Ah yes let's just forget that DNC and SGE are in Limsa, Pictomancer and GNB are in Gridania. Or that Limsa hosts the Heavensturn and Summer events, or that Gridania hosts the Halloween, Christmas, and Easter events. Yes, Ul'dah does have a slightly higher than normal count of jobs starting there, but RDM and SAM made sense to be there. I can't speak to Viper for it's reasoning, but RPR only had another option for Limsa but Ul'dah made more sense because it's easier for Garleans to blend into the city over whelmingly over loaded with refugees.

So in reality, I don't really see that Ul'dah is being over used more than any other city. If anything it only has a slight margin of increased traffic for jobs nothing more.