This setup is very customisable, it highly depends of the content you do and the speed of your group.
Mistform is pretty much mandatory for Necro as you will be late otherwise by using Potency so you need so somewhat make up for it. If you don't want to be vamp or if your tank is slow anyway, just swap it out.
If your group needs Banner from you in trash, you can cut Cloak and Archer instead.
If your group doesn't need your Colo, you can make an Acuity setup with Maeltrom staff and drop a fat Destro in big packs.
If your group is kinda slow to kill packs, you can use Azureblight instead of Sulxan, just make sure to Siphon first gcd when your blastbones/GE connects.
If you need more sustain, you can frontbar Goliath to proc necro passive.
Corpseburster is way better than Tideborn, but there is some packs where it will just not work, then you should use the secondary setup.
Velothi isn't the best mythic in trash anymore imo, if your group is optimised then Mora would be better for exemple. However, most of groups have very poor pen debuff and stacking, and might not give you minor force with Werewolf, so I would let it by default, and if you have a group checking all of that, you can swap to Mora.