It's because everyone's net damage goes up more because theirs isn't being reduced. Yeah only part of Necro strike will get the dampening aspect on it, but NO part of, say, a warriors mortal strike (to use your example) will feel the dampen. Lets say my Necro strike does 20k damage, and 40k absorb, and MS does 50k damage. The dampen the reduces (idk the numbers just pulling random things out) my damage from 60k total, to 50k total, to 40k total, etc. While the MS damage just stays at a static 50k. So yes, my damage still is hitting, but it's getting nerfed while other classes do not have to feel this.
Ok obviously you are special so let me help u. Flash Heal Heals a friendly target for 12619 to 14664 (+ 131.4% of Spell power).NS deals 100% weapon damage, absorbs the next (100 / 100 * Attack power)Mortal strike that deals 175% weapon damage
Ok now lets do a bit of math the average absorb of necro atm should be around 40k + your 100% weapon damage depending on your gear and professions.
Now for easier math lets say flash heals for 100k every time.
MS does 175% weapon damage and 25% on reduction of heals.
Ok lets start add numbers. Here I will keep necrotic absorbtion the same.
Flash MS NS %of absorbtion per flash
100k 175%+25%red 100%+ 40k absorb 40%
90k 185% + 22.5k 110% + 40k absorb 45%
80k 195% + 20k 120% + 40k absorb 50%
70k 205% + 17.5k 130% + 40k absorb 62%
And so on.
So suddenly your dumb ass necrotic absorbs from 40% to 62% of a heal when ms does 25%? Now before you say yeah but mortal strike does more damage dont forget that dk has 10000 more strikes that do insane damage. Necrotics have always been there to build pressure but with this new system the GCD worth of one necrotic per one heal becomes nearly double only with 30% of the damage boosted in. Also I dont know if you know but Blizzard balances necrotic strike with the average healing input of a healer. So when healers get nerfed so should necrotic get nerfed or scales insanely. Now please for the love of god stop talking bullshit.