Why is the Solar separate instance from Waking Sands / Rising Stone?

[Tint]

Isn't the Solar just an instance within what's already an instance? I've never seen any other players in the area outside the Solar, so why make it separate?

I think it is still not a single player instance but instead all the other players are just invisible. If you enter in a party you will notice that the other party members are listed as if they were on the same map - just greyed out like they are out of range. Same happens in the inn rooms.

So splitting the zones was likely done to lessen server stress when a lot of people watch long cutscenes on patchdays there.