Celestial revenant in PvE?
So far not really useful.
Revenants condition damage is poor in pve due to the majority comming from torment.
Revenants direct damage is superb.
Revenants have excelent survivablity and mobility without any defensive stats. If you are running tank in raids, you will pick pure thoughness trinkets and keep rest at peak damage due to timers on bosses.
No reason for celestial unless there are major changes to the class.