Really the only issue I see with Necro is that its a 2min CD vs a 1min CD that generates RP more quickly and faster when doing big AoE pulls.
While the Necro damage ability is nice and does good Rune Corruption procs it also pulls things to you that you might want to avoid, like Blood Gorger worms or the Slime adds that can cause screw ups if you get melee’d by them or pull them into the boss.
Door of Shadows can also be a good “GET OUT OF BAD NOW” cast if Wraith Walk is down. While Fleshcraft is just a bonus 20% that will likely get torn down by slow passive damage mechanics and not actually help save you from a big hit that you’ll just AMS/AMZ/IBF anyways.