PS: The Europe WoW Client now displays an 8-hour maintenance (3 to 11 CET), so patch 7.3.5 should go live this Wednesday (Tuesday in the US).
There will probably be some explaining done during the race recruit quest line or any starting quests they have. Void Elves are easy, they've been gone forever, Nightborne is gonna be interesting since..you know, they've been isolated for 10,000 years.