I am a newly-returning player to this game.
I played at launch, on Daggerfall Covenant as a vampire templar healer. I never even got to level 50. I recently came back and rolled a stamina-based templar tank, and while I love her to bits, I can't help but want to try something new. I know I'll make another healer at some point, and that's going to be yet another templar. So, I want to try something else - anything else.
Back when I was playing at launch, every group was comprised of templars and DKs. A few sorcerers here and there. Since I've been back for a couple of months, I've run well over 200 dungeons. Every group is comprised of templars, nightblades, and sorcerers. I can count on one hand the total number of DKs I've seen in PvE dungeons so far. I queue my templar as both tank and DPS, so I'm not always taking up the tank slot.
It's not even close. I counted up people in groups I ran this past weekend, and tallied the numbers overall. I saw about 60% templar, 30% sorcerer, 10% nightblade and 0% DK.
I was thinking of making a DK of some sort, but I'm really worried at the _complete_ lack of them I see in PvE.
Have they been massively nerfed?
I know - one of the benefits of this game is you can basically play whatever you like, in just about any capacity. I'm not afraid of making something that isn't "flavor of the month". Heck, my tank is a vampire - a terrible, terrible choice that I still like

. But if DKs have been nerfed to the point of no return, I don't want to try one and burn out on this game again. So, yes, I'm sure it's still viable; what I want to know is why they don't seem to be played anymore.