The problem with Archer breaking down to Bard is that the progression is asinine. An instrument playing class like Musician or something should have been introduced, and then broken down as Bard, and Archer should have broken down into something else like some kind of ranger or assassin wielding different arrows or something. Those kinds of progressions make sense.

Wielding a bow and a musical instrument are 2 completely different kinds of disciplines that in ANY kind of practical world, fantasy or otherwise, both require completely separate dedication and have nothing to do with one another.

Much like sticking a feather up your butt does not make you a chicken, sticking a harp/lyre/trumpet/whatever on a bow does not make an Archer a musician.