The biggest problem with MCH, as well as with DRK and AST, is the vast majority of people who play the job are BAD (many DRK and AST I've played with admit this is their first tank/heal job, so...). I cringe when I get a DRK, AST or MCH in the DF, not because their job is bad but because the players are. While I don't know any good DRK yet (I main WAR, so I don't play with a ton of other tanks in the first place) I do know some good AST and MCH and enjoy playing with them.

Yes, MCH and BRD need a slight buff to them, mostly QoL buffs, but they don't need a buff like what they want. Mobility comes at a cost, and I have seen BRD do top or almost top DPS in Bis EX, and many I've run with are at the middle in Rav EX (haven't run with MCH in the EXs yet, but know they do similar damage as BRD).

MCH (and AST and DRK) have a bad rap mostly because the job is new and the people who play them are bad.