With two weeks to go for release of 8.3 I ran the opening quest chain again on my main, then on an alt over the weekend.
From start to the first mini-vision quest (obtaining the cloak just prior) it took me 2h 10m (video here: https://youtu.be/C9xvjOHS-gM). There’s more questing beyond this point. No skip for alts. Some of the quests may take longer after release because of other players. Lots of travel involved.
This is by far the longest patch quest chain I can ever remember. The fact it doesn’t enable skipping with alts is going to cause a lot of frustration. 2-3 hours is a lot to ask for each alt someone might want to play.