Well, story wise at the end of 2.55 it would be a bit hard for us to get any kind of promotion in a GC (especially in Ul'dah), until that whole... unpleasantness.... is sorted out.

So I don't expect the available GC ranks to be raised any time soon (and hence, when SE does eventually increase the ranks, it will almost definitely require Heavensward and expansion story progress to gain such promotions, for the lore reasons I mentioned).