Feel free to add your own opinions or advice you would like to share on how to take advantage of these skills.
*Grudge Strike's damage has been increased by 200% of weapon damage.
*Dark Taboo's damage has been increased by 200% of weapon damage and now heals for a minimum of 2000 Health based on Soulforce, up from 800 to 2000.
*The Primal World version of Stunning Blow has had its damage increased by 200% of weapon damage.
*The Primal World version of Malefic Crush has had its damage increased by 400% of weapon damage.
*Ultimate Summoning's now deals double base magic damage.
Before Primal Warfare, the skills Grudge Strike, Dark Taboo and Stunning Blow dealt about 80,000 - 90,000 damage in PvE (160,000 - 180,000 Critical Hits). Malefic Crush dealt about 100,000 - 110,000 damage (200,000 - 220,000 Critical Hits). After the update, Grudge Strike, Dark Taboo and Stunning Blow deal about 120,000 - 130,000 damage in PvE (240,000 - 260,000 Critical Hits). Malefic Crush deals about 170,000 - 180,000 damage (340,000 - 360,000 Critical Hints). The damage was tested with this gear: http://mypers.pw/9/#463330
In PvP, these skills dealt about 900 - 1100 damage (1800 - 2200 Critical Hits) on an endgame geared Assassin (R9rr +12, JOSD, non-rebirth Nuema Portal). Now, they deal about 1300 damage (2600 Critical Hits), while Malefic Crush deals about 1800 damage (3600 Critical Hits). The damage was tested with this gear: http://mypers.pw/9/#463330
I was able to deal up to 11,000 damage per Critical Hit on a R9rr Arcane Armor player with 20,000 physical defence. A fairly endgame-level geared Demon Venomancer was able to hit me for 11500 (23000 Critical Hit) damage with Grudge Strike and 17400 (34800 Critical Hit) damage with Malefic Crush while I had the 0 physical defence debuff on me.
At max Soulforce (54300), Dark Taboo healed me for about 5300 HP per hit.
Note that numbers are based on one example only. Numbers will vary depending on your gear, who or what you attack, whether they have buffs or debuffs on etc.
The damage boost of the Fox Form attack skills is nice. They are now viable in PvP. There are times when I've just turned into Fox Form but the opponent is one hit away from dying. Sometimes changing forms and casting an attack takes long enough for the opponent to run away and escape alive. Now, you can actually use these skills to finish people off. This is especially true against Arcane and Light Armor classes.
The update on Dark Taboo is nice, but it's not something that you can rely on in PvP. Still, there might be a few occasions where it might come in handy. That's to be seen. Ultimate Summoning got a nice boost in damage so now you may want to pick your targets more carefully. You can actually kill with this skill now, and if the opponent dies too early the effects won't go off.
There's not much to say about these skills in terms of PvE. Damage boost is always nice, and Dark Taboo became a better HP pot saver.