OK, compared to the Archer the -7Q is better armored, can continuously move and fire it's main weapons and has improved support capability from those -5 racks. It loses out slightly in speed, but that isn't a major problem for the role they fill and if for some reason it is you should probably be using a lighter, even faster design. It also lacks rear firepower. This last can be fixed by dropping four heat sinks for rear firing lasers and some more armor, or maybe armor and jumpjets?
So why then so both the Longbow and the Archer exist? The Longbow should have replaced the Archer, with the later receding into history (at least until after the Succession Wars broke out). And having both, why did the FWL accept the Yeoman?