The way I see it, there's just no content in-game yet that requires an alliance of FCs.. It likely got delayed until after the duty finder changes which will allow queueing up as a full alliance for Frontline. The side effect is that the changes should also make it possible to sign up as a full alliance for CT then.

The roaming primals they mentioned in the English live letter, they're just not certain how to implement it yet, and make it possible for smaller FCs to get the right to summon instead of just the large FCs that can perma-camp the zones they'd roam in ...