DK was good before the buffs, it will be good after the nerfs. Not top tier like it is now because it won't be a healer-tank-damage-dealer, will lose potency. But still good.

Might have to go back to running infused cost reduction, or might get away with just Wretched Vitality

Me and my wife made a magdk for PvP because of all the posts about dk being op posts and videos everywhere. We are currently sitting at around 600 cp for PC accounts. before we had a templar that we tried making fairly tanky, though one thing we could notice straight. Dk is way more tanky without building it that way. In comparison templar is reaaaly squishy even with defensive sets, jab hits rarely land at its fullest because of everyone running speedy movement speed buffs/traits and whatnot, BUT dk really lacks in good damage if you go for too much defense. If you don't make use of combustion the sustain is really bad too.

We tried nearly all the setups on the internet like suggested by the most popular streamers as well as builds from build sites. In bg's you can absolutely dominate the show. In cp cyrodiil though, if you don't have enough cp and if you don't literally every overperforming cp there is, you will lack behind. You can run pariah and vamp stage 3 and still melt in no time. If you go snb your most reliable self-heals will be spamming coag blood but thats only possible if your sustian is enough (as mentioned before, making use of combustion = charged trait/s on your weapon/s). BSW helps with that a bit, since it burning straight away with using a flame damage skill.

Currently we running something inferior to most other builds in terms of stat density, but more comfortable in terms less bar swap for being tanky.

Pariah body + ring and neck
1 pc magma
BSW dw double charged flame+poison glyphs and 3 piece body (small parts)
malacath
2 spell cost reduction glyphs 1 weapon power glyph
potato snb backbar
atro mundus
sugar skulls
tri-pots
vamp stage 3

Its pretty tanky because resists are double barred. Damage is not bad and still enough to delete pugs. But this is also absolutely inferior when fighting even a single 1k++ cp vet player running at least double dps sets + resto + that annoying speed runaway LoSing kind of playstyle. Being a duo helps but not much tbh. We thinking about going swift on jewelry ourselves to somewhat have an easier time chasing. Though you have players here who play ring around the rosie for literal hours so, if you not into that you can also just make it all infused for more sustain and damage. Be on the backbar most of the time and block incoming bombs while spamming coag blood to heal through the damage. Can survive certain bombs that way.

The most usual builds with defensive sets backbarred tend to get you killed if you dont barswap in time in case you dont see bomb coming or if barswap not working. If you run with a group you can backbar a damage set that carries over to the frontbar, frontbar damage set too, as well as either another damage monster set and mythic or a more defensive monster set like chudan. Stacking heals even in small scale with 3-4 leads to people being literally unkillable while abusing LoS and speed buffs to its fullest on top.

At the end I can comfirm what others are saying here though. Dk way easier to play than all other classes rn in cp cyrodiil at least and lets you live a bit longer with easy to get sets are more than enough to somewhat stand your ground. But its far from being op regardless how you build it. You will explode if you have not enough cp, not enough good players in your group or helping with fights like healing or making up for whatever misses from your build, small scalers will still delete you with their timed burst and bombs will still be the main reason you die no matter how hard you try.

I suggest not trying to hard on finding the sweet spot with a build no matter what class as the meta currently really is far from being forgiving compared to running in a ball or small scale organized group. Its them who stick with everything that overperforms in any way. DK is in these compositions is either rare or non existant.

Been playing this game since release with breaks. My original account is from old veteran rank days. Made a new account for consoles for me and my wife years ago, where we settled first. Made the move over to PC because PvP on console is an unplayable mess on every server, every timezone.

So yes, after all these years any of the cp systems have had huge impact on wether or not you can be competitive. You either play at a constant damage/sustain/utility/mitigation disadvantage or you are at least in this regard on par with the rest once you cought up. But that's a different story. its only important if op is really low on cp's then only real option to not be completely useless would be to pick a different class and switch to healer.

Some setups turn out well, some don't. Been running the setup mentioned above for quite a while but like I said, its far from perfect. 5/5/2/1/1 while tower humping is way to go nowadays, more stat dense and can net you more success regardless what you wanna do in PvP, IF you are comfortable with constant barswap, and reacting in time to whatever happens. Have seen many people struggling with the usual meta builds. Having a defensive set being active on both bars can help those who have a hard time with them.

But in the end it doesn't matter much. Current meta is just busted. You can't do much about it other than running what feels like 99% of players are doing too (swift/daedric/markyn/damage and monster set of choice) while LoSing like a madman or forget about all the theorycrafting as it stands and just use a build from any of the more organized guilds doing small scale or ball groups.

High Isle will bring another big shift to builds. Though the meta as we know it won't suddenly lead to people stop hugging stones, stairs or trees. The cp nerfs and the new gear that gets introduced with it looks like it might make entry to PvP easier and makes cp's a little less important for the lower boosts they will give from the blue tree.