So what you are saying is that the next melee class added should be red mage? Or is 4 melees with instant weaponskills not too homogeneous?
Because I think a red mage is very much a needed class.

As to the fact they are all casters, while I do agree adding a cast time to bard's abilities was a bad idea, none of them feel the same
Machinist seems to work well with their abilities as far as other people have said, I have not unlocked gauss barrel so cannot comment on it, it just feels tacked on with bard.