Looking at your post, I agree with Phantom Force once more, but for a different reason. I think that Phantom Force would be beneficial to Revenankh as it sticks to its pseudo-concept of being the best Bulk Up user while giving it a power boost that makes it viable in today's metagame. Here is a set that would be best with Phantom Force.The power drop alone between the two is amazing. The entire purpose of an offensive Z-Move is to break through one of the opponent's defensive checks to your Pokemon. As I've already pointed out and has been present in every calculation made in attempt to prove Phantom Force is too powerful, the calculation requires Bulk Up to have been used first. So not only must you switch Revenankh in, you must take a hit or deal with another potential unfavorable switch to set up Bulk Up.
Mechanically, it's best to compare Life Orb Shadow Claw vs. Ghostium-Z Phantom Force, because Ghostium-Z Shadow Claw is directly inferior to Life Orb Shadow Claw. At 140 Base Power, Gho-Z Shadow Claw does not boost damage enough to consider it over Life Orb. Accounting for the Life Orb boost, successive Shadow Claw's would have around 182 BP to Gho-Z Phantom Force's 175. The difference of course being two instances of Life Orb recoil and no specific need for Bulk Up.
But to illustrate that, let's look at the moment where +1 252 Adamant Z-Shadow Claw stops guaranteeing OHKOs against generally relevant threats:
Scizor-Mega (OU Offensive Swords Dance) Never-Ending Nightmare 85.7 - 101.4% 12.5% chance to OHKO
Clefable (OU Utility) Never-Ending Nightmare 85.2 - 100.5% 6.3% chance to OHKO
Clefable (OU Magic Guard + Calm Mind) Never-Ending Nightmare 85.2 - 100.5% 6.3% chance to OHKO
Magearna (OU Choice Specs) Never-Ending Nightmare 81.3 - 95.7% guaranteed 2HKO
Sableye-Mega (OU Showdown Usage) Never-Ending Nightmare 80.2 - 94.7% guaranteed 2HKO
Magearna (OU Assault Vest) Never-Ending Nightmare 79.3 - 93.3% guaranteed 2HKO
Gyarados (OU Mega Dragon Dance) Never-Ending Nightmare 79.1 - 93.3% guaranteed 2HKO
Celesteela (OU Specially Defensive) Never-Ending Nightmare 78.6 - 92.9% guaranteed 2HKO after Leftovers recovery
Magearna (OU Offensive Trick Room) Never-Ending Nightmare 78.5 - 92.5% guaranteed 2HKO
Venusaur (OU Defensive Tank) Never-Ending Nightmare 78.5 - 92.7% guaranteed 2HKO
Slowbro-Mega (OU Defensive) Never-Ending Nightmare 77.8 - 92.1% guaranteed 2HKO after Leftovers recovery
Zygarde (OU Dragon Dance) Never-Ending Nightmare 76.7 - 90.7% guaranteed 2HKO
Scizor (OU Bulky Swords Dance) Never-Ending Nightmare 76.3 - 90.3% guaranteed 2HKO
Gliscor (OU Swords Dance) Never-Ending Nightmare 75.8 - 89.4% guaranteed 2HKO
Pelipper (OU Physically Defensive) Never-Ending Nightmare 75.5 - 89.1% guaranteed 2HKO
Venusaur-Mega (OU Offensive Tank) Never-Ending Nightmare 75.4 - 88.8% guaranteed 2HKO
Gyarados (OU Substitute + Dragon Dance) Never-Ending Nightmare 74.2 - 87.5% guaranteed 2HKO after Leftovers recovery
Rotom-Wash (OU Defensive Pivot) Never-Ending Nightmare 74.2 - 87.4% guaranteed 2HKO after Leftovers recovery
Charizard-Mega-X (OU Bulky Will-O-Wisp) Never-Ending Nightmare 73.8 - 87.1% guaranteed 2HKO
Landorus-Therian (OU Offensive) Never-Ending Nightmare 73.6 - 86.8% guaranteed 2HKO
Landorus-Therian (OU Choice Scarf) Never-Ending Nightmare 73.6 - 86.8% guaranteed 2HKO
Landorus-Therian (OU Double Dance) Never-Ending Nightmare 73.6 - 86.8% guaranteed 2HKO
Skarmory (OU Specially Defensive) Never-Ending Nightmare 72.1 - 85.3% guaranteed 2HKO after Leftovers recovery
Suicune (OU Substitute + Calm Mind) Never-Ending Nightmare 71.2 - 83.9% guaranteed 2HKO after Leftovers recovery
Tapu Fini (OU Defensive) Never-Ending Nightmare 71.1 - 83.9% guaranteed 2HKO after Leftovers recovery
Scizor-Mega (OU Pursuit) Never-Ending Nightmare 70.8 - 83.3% guaranteed 2HKO
Here's the same cohort with Adamant 252 Life Orb Shadow Claw:
Scizor-Mega (OU Offensive Swords Dance) Drain Punch 40.2 - 47.6% guaranteed 3HKO
Clefable (OU Utility) Shadow Claw 37 - 43.9% 99.8% chance to 3HKO after Leftovers recovery
Clefable (OU Magic Guard + Calm Mind) Shadow Claw 37 - 43.9% 99.8% chance to 3HKO after Leftovers recovery
Magearna (OU Assault Vest) Drain Punch 36.9 - 44% guaranteed 3HKO
Celesteela (OU Specially Defensive) Drain Punch 36.6 - 43.4% 99.3% chance to 3HKO after Leftovers recovery
Magearna (OU Offensive Trick Room) Drain Punch 36.5 - 43.1% guaranteed 3HKO
Zygarde (OU Dragon Dance) Drain Punch 36.1 - 42.5% guaranteed 3HKO
Scizor (OU Bulky Swords Dance) Drain Punch 35.5 - 42.5% guaranteed 3HKO
Sableye-Mega (OU Showdown Usage) Shadow Claw 35.1 - 41.4% guaranteed 3HKO
Charizard-Mega-X (OU Bulky Will-O-Wisp) Drain Punch 34.8 - 41.2% guaranteed 3HKO
Rotom-Wash (OU Defensive Pivot) Drain Punch 34.6 - 41.2% 65.3% chance to 3HKO after Leftovers recovery
Gyarados (OU Mega Dragon Dance) Shadow Claw 34.4 - 41% guaranteed 3HKO
Venusaur (OU Defensive Tank) Shadow Claw 33.9 - 40.6% guaranteed 3HKO
Skarmory (OU Specially Defensive) Drain Punch 33.8 - 40.1% 37% chance to 3HKO after Leftovers recovery
Slowbro-Mega (OU Defensive) Shadow Claw 33.8 - 40.4% 36.7% chance to 3HKO after Leftovers recovery
Gliscor (OU Swords Dance) Shadow Claw 33.2 - 39.2% 100% chance to 3HKO
Pelipper (OU Physically Defensive) Shadow Claw 33.1 - 39% 99.8% chance to 3HKO
Suicune (OU Substitute + Calm Mind) Drain Punch 33.1 - 39.6% 15.1% chance to 3HKO after Leftovers recovery
Scizor-Mega (OU Pursuit) Drain Punch 32.9 - 39% 99.8% chance to 3HKO
Venusaur-Mega (OU Offensive Tank) Shadow Claw 32.8 - 38.9% 99.2% chance to 3HKO
Gyarados (OU Substitute + Dragon Dance) Shadow Claw 32.2 - 38.5% 2.5% chance to 3HKO after Leftovers recovery
Landorus-Therian (OU Offensive) Shadow Claw 32.2 - 38.2% 97.1% chance to 3HKO
Landorus-Therian (OU Choice Scarf) Shadow Claw 32.2 - 38.2% 97.1% chance to 3HKO
Landorus-Therian (OU Double Dance) Shadow Claw 32.2 - 38.2% 97.1% chance to 3HKO
Clefable (OU Unaware + Calm Mind) Shadow Claw 31.7 - 37.5% 0.1% chance to 3HKO after Leftovers recovery
Tapu Fini (OU Defensive) Shadow Claw 31.1 - 36.7% guaranteed 4HKO after Leftovers recovery
In many of these instances you are going to alternate moves and use your stronger Drain Punch for healing off Life Orb recoil. You really don't need Bulk Up for the Life Orb set, you can run Ice Punch or other coverage. In essence, having Shadow Claw but not Phantom Force makes a Bulk Up Set less viable. Why should Revenankh use a moveslot on Bulk Up when it can sufficiently damage with Life Orb and 3 Attacks + Moonlight? Unless it can efficiently break some of these strong meta threats like Mega-Scizor, Clefable, Mega-Venusaur, and Mega-Sableye it will struggle in the CAP metagame.
Here's the cohort with +1 Adamant Ghostium-Z Phantom Force:
Scizor-Mega (OU Offensive Swords Dance) Never-Ending Nightmare 139.1 - 164% guaranteed OHKO
Clefable (OU Utility) Never-Ending Nightmare 137.8 - 162.6% guaranteed OHKO
Clefable (OU Magic Guard + Calm Mind) Never-Ending Nightmare 137.8 - 162.6% guaranteed OHKO
Kyurem-Black (OU Icium Z Wallbreaker) Never-Ending Nightmare 134.5 - 158.5% guaranteed OHKO
Kyurem-Black (OU Mixed Wallbreaker) Never-Ending Nightmare 134.5 - 158.5% guaranteed OHKO
Kyurem-Black (OU Choice Band) Never-Ending Nightmare 134 - 157.8% guaranteed OHKO
Magearna (OU Choice Specs) Never-Ending Nightmare 131.3 - 155.3% guaranteed OHKO
Sableye-Mega (OU Showdown Usage) Never-Ending Nightmare 129.9 - 152.9% guaranteed OHKO
Heatran (OU Bulky) Never-Ending Nightmare 129.5 - 152.8% guaranteed OHKO
Celesteela (OU Specially Defensive) Never-Ending Nightmare 128.3 - 151.2% guaranteed OHKO
Gyarados (OU Mega Dragon Dance) Never-Ending Nightmare 128.3 - 151% guaranteed OHKO
Magearna (OU Assault Vest) Never-Ending Nightmare 128 - 151.5% guaranteed OHKO
Venusaur (OU Defensive Tank) Never-Ending Nightmare 127.5 - 150.1% guaranteed OHKO
Magearna (OU Offensive Trick Room) Never-Ending Nightmare 127.4 - 150.2% guaranteed OHKO
Slowbro-Mega (OU Defensive) Never-Ending Nightmare 126.9 - 149.6% guaranteed OHKO
Zygarde (OU Dragon Dance) Never-Ending Nightmare 124.9 - 147.3% guaranteed OHKO
Scizor (OU Bulky Swords Dance) Never-Ending Nightmare 124.1 - 146.6% guaranteed OHKO
Gliscor (OU Swords Dance) Never-Ending Nightmare 123.2 - 145.4% guaranteed OHKO
Pelipper (OU Physically Defensive) Never-Ending Nightmare 123.2 - 144.8% guaranteed OHKO
Venusaur-Mega (OU Offensive Tank) Never-Ending Nightmare 122.8 - 144.5% guaranteed OHKO
Gyarados (OU Substitute + Dragon Dance) Never-Ending Nightmare 120.3 - 141.6% guaranteed OHKO
Rotom-Wash (OU Defensive Pivot) Never-Ending Nightmare 120.1 - 141.5% guaranteed OHKO
Charizard-Mega-X (OU Bulky Will-O-Wisp) Never-Ending Nightmare 119.7 - 141.5% guaranteed OHKO
Landorus-Therian (OU Offensive) Never-Ending Nightmare 119.7 - 141% guaranteed OHKO
Landorus-Therian (OU Choice Scarf) Never-Ending Nightmare 119.7 - 141% guaranteed OHKO
Landorus-Therian (OU Double Dance) Never-Ending Nightmare 119.7 - 141% guaranteed OHKO
Skarmory (OU Specially Defensive) Never-Ending Nightmare 117 - 138% guaranteed OHKO
Tapu Fini (OU Defensive) Never-Ending Nightmare 115.1 - 135.5% guaranteed OHKO
Remember, these calculations require a safe-switchin, the use of Bulk Up, and the avoidance of an intervening KO. After Gho-Z is exhausted, Revenankh cannot just click Phantom Force and expect to get a neutral hit. I would also note there is enough buffer here that you could run a more defensive Revenankh spread with Careful and still net many of these OHKOs.
In summary, +1 Z-Phantom Force makes a Bulk Up breaker set legitimately more viable than a Life Orb 3 Attacks Set, whereas boosted Z-Shadow Claw's failure to provide sufficient offensive pressure means Revenankh's two major sets will become Life Orb 3 Attacks and Choice Band. Will there still be some Life Orb sets that run Bulk Up? Probably, but without a set that allows Revenankh a bulkier build it will become solely an offensive Pokemon with good defenses rather than a defensive Pokemon that can break through opposing defenses given time to set up.
RE: Stone Edge and Healing Wish:
Stone Edge is only marginally more useful than Rock Slide, and you'd primarly be aiming it at Volcarona, Pyroak, and Gyarados before Mega-Evolving (or Fly-Z Gyara on the switch). I think it's fine as a consistency move, a ton of Fighting types learn Stone Edge.
Healing Wish is just adding for the sake of adding. It's also explicitly against Revenankh's general way of playing, which is to be a difficult to KO offensive or defensive presence with un-resisted STAB. Sacrifice moves aren't Revenankh's bag.
Revenankh @ Ghostium Z
Ability: Triage
EVs: 252 Atk / 252 SpD / 4 HP
Careful / Adamant Nature
- Bulk Up
- Phantom Force
- Drain Punch
- Ice Punch / Moonlight
This set takes full advantage of Phantom Force. The main reason behind the special defense investments are this:
252 SpA Tapu Lele Psychic vs. 4 HP / 252+ SpD Revenankh in Psychic Terrain: 300-354 (93.1 - 109.9%) -- 56.3% chance to OHKO
252 Atk Revenankh Phantom Force vs. 0 HP / 4 Def Tapu Lele: 320-378 (113.8 - 134.5%) -- guaranteed OHKO
The investments allow Revenankh to (albeit, unreliably) survive a Psychic from Tapu Lele. In return, a non-boosted Phantom Force can OHKO Lele. Before you cry it makes it OP...
252 Atk Revenankh Shadow Claw vs. 0 HP / 4 Def Tapu Lele: 252-296 (89.6 - 105.3%) -- 37.5% chance to OHKO
Shadow Claw may OHKO anyways. Also...
+1 252 Atk Revenankh Shadow Claw vs. 0 HP / 4 Def Tapu Lele: 372-440 (132.3 - 156.5%) -- guaranteed OHKO
At +1, Shadow Claw OHKOs. With these investments, the only way Lele could stop Revenankh is if it already was on the field when it enters. Revenankh is going to have an improved matchup against Lele no matter what we do.