Not sure if anyone added this, but there is one reason I seriously doubt Ishgard will ever give us the option of a GC; the Four Houses. I can't remember where, but I'm pretty sure one of the things heavensward was going to add was picking one of the 4 houses to side with instead of a GC. This can offer, if done right, 4 stories to enjoy as you move up with a selected house. I'm willing to bet house Fortempts may even offer a certain shield as a max level reward.

You get our allegiance to Ishgard, PVP is still itself, and possibly actual story and insight to the other houses. Sounds like a win to me.