Perhaps a Simple DRK Solution

[Nektulos-Tuor]

Very cool to know its multiplicative and not additive. I wasn't sure if subsequent skills took into account the effects of previous ones or just used the base statistic. Considering that is the case I still think BfB functions well with Grit. Being that the skills are multiplicative I actually think it makes BfB better. With additive we were talking about an increase of 25% in damage taken for a 10% increase dealt according to your your numbers its actually an increase of 18.75% damage taken for a 9% increase to damage dealt. You are absolutely correct that straight dropping Grit gets you to higher dps numbers, however it costs a significant amount of MP and a GCD - doubled if you need to return back to Grit stance. Adding BfB means in times where actual stance dancing is too risky you can still pseudo stance dance.

Normal=1.0x damage.

Why would you.. activate a B4B in Grit.. when you could drop Grit, get even MORE damage and not take as much damage?

Normal+Darkside+B4B=1.25x damage.
Normal+Darkside=1.15x damage.
Normal+Darkside+Grit=0.92x damage.
Normal+Darkside+Grit+B4B=1.0x damage. The same damage.. for just being normal.

So your idea, doesn't make a lick of sense. You would do 15% more damage just using Normal+Darkside. With Normal+Darkside+Grit+B4B your taking even more damage with 15% less damage.