I'm Stunned -- actualy I'm not
One of the problems I ran into is that Paladins lack an AoE stun. Sure, we have Blinding Light, but it's a disorient, and it breaks on any non-Holy damage. It's great when you are soloing, but unless you run with all Paladin group, the disorient is going to break in about a millisecond. Other tanks have true AoE stuns that do not break on damage. They can assist with the stun rotation. I can't. Consecrated Ground / Divine Steed helped a little bit with kiting, but I still was wishing for a true stun like other tanks have.
Phenomenal Cosmic Power, Itty Bitty Health Pool
The other problem I had is that Paladins are balanced around our ability to self-heal which leads to us having the smallest health pool of any tanking class. Necrotic takes all that self-healing away. I died on many pulls. The spider and bat gauntlets were painful. At one point, I wasn't sure we were going to be able to clear those bats. Druids have a giant health pool, Warriors have the incredible mitigation of Ignore Pain. Monks have the 100% avoidance built into Exploding Keg.
First time in a long time I felt like being a Paladin tank was a significant hindrance to my team.
Even though we slogged through and finished the dungeon, we failed the timer. It felt like Necrotic had exacerbated every one of my weaknesses and while I knew it wasn't true, I felt responsible for the our lack of success.
I was frustrated and angry when I logged off and banged out a rant of a blog post that thankfully stayed safely in the 'Draft' folder. The next day, I could look at it with a bit more clarity. At about 875 item level, +9/10 is about the limit of our group right now and Black Rook isn't the easiest dungeon on Mythic +anything. I also hit up Twitter and Discord and discovered that there were elements of my kit like Blessing of Spell Warding or Final Stand that I had not considered. I face-palmed pretty hard.
I love playing my Paladin tank and I enjoy the way our healer roots are incorporated into our tank kit. In a strange way, I'm looking forward to Necrotic coming up again in the rotation to see how much better I can do with what I've learned.