Ayy MCH has 8 times less clears on the Final Omega than Bard.

[Bourne_Endeavor]

Simpler put - get rid of piercing / slashing / blunt.

This would kill MCH completely. Without Piercing, MCH offers next to nothing compared to Casters. It's biggest selling point is higher overall damage. Taking away 5% means it's pulling substantially less than even RDM. Coupled with its immense unpopularity and you now have a job no one will even look at, let alone get invited to any static. Frankly, all three will need something to compensate for a 5% damage loss. BRD may have great synergy with DRG but it will struggle to make up the difference a SMN or BLM offers. DRG will be in an odd spot since Slashing and Blunt are, technically, stronger than Piercing.

[Sunako]

This would kill MCH completely. Without Piercing, MCH offers next to nothing compared to Casters. It's biggest selling point is higher overall damage. Taking away 5% means it's pulling substantially less than even RDM. Coupled with its immense unpopularity and you now have a job no one will even look at, let alone get invited to any static. Frankly, all three will need something to compensate for a 5% damage loss. BRD may have great synergy with DRG but it will struggle to make up the difference a SMN or BLM offers. DRG will be in an odd spot since Slashing and Blunt are, technically, stronger than Piercing.

That only tell mch is either too weak or bard is too overpowered. Mch is not supposed to compete between other casters. If one ranged have permanent spot and other 3 casters and mch compete from one spot, something is really wrong.

[Bourne_Endeavor]

Even assuming they completely remove disembowel without making any adjustment to brd pdps, brd would more than likely still be meta because of refresh, since in a speedkill environment healers' combined dps is basically as high as a blm's. Refresh alone is worth at least 1k combined healers dps. Which is way claiming that BRD is dependant on DRG is not really correct. It actually is the other way around.

This is actually quite debatable. While Refresh is undoubtedly better, Mana Shift is no slouch either. Without any compensation, Bard will be pulling close to a 1,000 rDPS below Black Mage and 400-500 below Summoner. More than likely Astros will actually use Ewers for MP a bit more and run Casters. I do agree, however, Dragoon is more dependent on Bard than the other way around. In a scenario where only Piercing is removed but Blunt and Slashing remain, Dragoon straight up dies.

[Dualgunner]

This is actually quite debatable. While Refresh is undoubtedly better, Mana Shift is no slouch either.

Mana Shift is only really comparable to Goad. It's Goad, but for Mana instead, and unlike Tactician, Refresh, and Goad, it doesn't generate resource but instead transfers it. To compound, only one caster can really use it without any outwardly negative effects (SMN); in a no-BRD environment, RDM only just barely has the MP economy to sustain its own rotation, and forget Verraise if you're depending on them for Mana Shift; BLM faces potential rotation disruption due to mana ticks if they use Mana Shift at the wrong time, and "the wrong time" is virtually everywhere in their rotation.

All this to say...yes, Mana Shift is a big slouch in my opinion.