It is a thing though that a Selfish DPS needs to bring enough DPS to make up for the amount of utility its competing classes bring for the slot. MCH does not bring that, which means that yes its inherent problem can be solved by simply buffing its DPS to the point mobility tax effectively does not apply specifically to it.

Are there a lot of design issues that MCH needs fixed? Yes. One of those design issues is not doing enough DPS to warrant the Selfish DPS title. So either expand its utility options to make it fall in line with the others in the role... or remove what utility it does have (Tactician) and ramp up its damage to the point that it is indisputably the BLM/SAM of the Physical ranged.