The main issue is Disembowel. All things being equal I'm usually at the top of pars in the content I do on my BLM, but generally the other people in the content I do are not top tier or really caring so much about going all out like I do.

The issues lies in synergy.

Let's pretend that BLM is top DPS in all content by straight up numbers. But bring in the synergy that BRD/MCH/NIN/DRG have and they all buff each others damage beyond what 4 BLMs performing at the same level could do even though their personal DPS numbers might be the highest.

I don't want to see that synergy removed to make BLM more viable, I would like BLM to be boosted to compensate.

All in all I agree with everything you said.