Which classes to focus for Desynthesis?

[AttacKat]

ALC: lots of ... weapons
ARM: but no primal weapons.
BSM: lots of primal weapons
CRP: a few primal weapons
GSM: couple of primal weapons
LTW: only 1 primal weapon (mog fists)
WVR: no weapons

Since I have not gone down the path yet, why all this focus on weapons? IME any DoW/M gear will drop battlecraft, and DoH/L gear will drop fieldcraft.

jc