MCH's Gauss Barrel feels less clunky than BRD's Wanderer's Minuet imho, simply because MCH was designed with GB in mind and they have a skill that lets you instant cast it for your Wildfire combo everytime it's up. I'm pretty sure they wern't planning on adding Wanderer's Minuet when they originally designed bard and it's playstyle.

I also don't see any real lack of damage for either of them... MCH parses about the same numbers as bard and they've always been below the "full dps" in return for having high mobility and strong support aspects.