What was they thinking when they did variant dungeons and criterion

[DPZ2]

They did it with island sanctuary, which is dead now.

I find this outlook a bit odd. Island Sanctuary is only "dead" to those who've completed it at level 90. It doesn't require other people to play it, provides a few interesting glamour items and mounts/minions, and is quite likely to be very much alive for all of those up-and-coming players who haven't reached level 20, let alone level 90. Same thing for the Variant dungeons. If it's soloable, and there are rewards people want from it, it will never be "dead".

It's just content that you can't do over-and-over-and-over again. And that's ok.