I'm going to assume the JP wiki hasn't updated all her skills yet because if not, it doesn't seem like much of an improvement towards her regular skills. The additional +20 party burst gauge when bursting seems nice though, in addition to her other +20 party burst gauge skill.
You can think of that in reverse and question why Uriel got an awakening before Amaterasu or look at water and question why Ea is the only water SSR to have gotten one. There may not have been any official reasons for awakening order but one can easily speculate 'balance' plays a part in it.