It's completely unneeded though. Suramar put on a shield because there was a Legion army marching on it to punish them for sealing the second portal that Suramar couldn't fight alone and the only one to help them was Ashamane who only slowed them down, giving the people of Suramar the time to construct the shield. It was either shield or annihilation, with Suramar being unable to help the rest of the Night Elves if they got obliterated anyway.