They should really stop calling this early access and start calling it open beta. It was the same for heavensward unplayable until early access is over. Oh you get disconnected? here is a 3 hour queue, but here's something you'll really like. We created a bottleneck in the MSQ just for you, because we know you like that!
Reminds me of wow and their garrison quest other game exact same issue; developers not thinking/ preparing what will happen when there are a lot of players trying to get into the same instance.
It can't be that hard to temporarily increase the instance/ login server capacity when you release a big expansion for a big game!