I asked Lead Flashpoints and Operations Designer Jesse Sky about the respawn timer on the Nightmare Pilgrim. He said that now that server populations are more dense on our destination servers, it makes sense to reduce the respawn timer. In a future update, it will be lowered to 30 minutes, and we'll continue monitoring feedback about it!
As another player said, can we get this for at least Gargath and Primal? And possibly the other WB's down to an hour.