Well if they are not going to make the damage buff last for 30s with Incarnation, then it is going to fall significantly behind Savage Roar.
Currently ranked:
(Pre-setbonus & no 100% Shred Crit)
1. Savage Roar + Jagged Wounds
2. Savage Roar + Elune's Guidance (- 5.8%)
3. Incarnation + Elune's Guidance (- 10.14%)
4. Incarnation + Jagged Wounds (- 13.49%)
(4p Set bonus + 100% Shred Crit
you'll get this due to +15% crit chance from artifact trait + 5% from raid, only needing 30% from gear, less if blood scent is taken)
1. Savage Roar + Elune's Guidance
2. Savage Roar + Jagged Wounds (- 1.8%)
3. Incarnation + Elune's Guidance (- 6.9%)
4. Incarnation + Jagged Wounds (- 14.1%)
IF the trait buff of 15% gets added to the entirety of Incarnation duration:
(Pre-setbonus & no 100% crit on Shred)
1. Savage Roar + Jagged Wounds
2. Savage Roar + Elune's Guidance (- 5.78%)
3. Incarnation + Elune's Guidance (- 5.87%)
4. Incarnation + Jagged Wounds (- 9.4%)
(Set bonus & 100% crit on Shred)
1. Incarnation + Elune's Guidance
2. Savage Roar + Elune's Guidance (- 1.4%)
3. Savage Roar + Jagged Wounds (- 4.99%)
4. Incarnation + Jagged Wounds (- 13.7%)
In other words, SR will be King of the Jungle if Incarnation does not extend the % dmg bonus to 30s.
If it does, then, they both will be within 1% of each other with set bonus.
As predicted, Jagged Wounds will fall behind once the 4p set bonus comes into play.
Finally, Elune's Guidance seems pretty strong since it is, in theory, giving you 2 free finishers every 45s.
It pairs well with Savage Roar since you can easily force a SR refresh with this as well as gives a smoother opener with SR up right off the bat and Rip up shortly.
EG > SR | Prowl > Rake > Shred > Rip | AF > FB
Basically you use your initial burst of 5 to pop SR, then get an improved rake in - if it crits and you have 5 CP, go Rip; if not Shred > Rip. Ashamane's Frenzy + remaining EG will give you enough for FB.
It also lets you use Bloodtalons efficiently, as SR/JW kinda forces you to take Moment of Clarity; SR/JW/BT is still unmanageable as it stands.
Bloodtalons will easily be the best T100 talent due to how strong it is and the legendary that is tied to it.