If actual usage numbers (which is severely limited insofar as to consider it "unrepresantative") shouldn't obstruct a certain type of armament from appearing in the game...
... then why should actual status of the armament, experimental or not, be any different?
The point is, the line has to be drawn somewhere.
The 109s and 190s had almost every combination of armament available to the Luftwaffe, categorized and made available for use as official Umrustsatz and Rustsatz modification kits and yet, in the game, only the most represantative forms of such armament variations are allowed. The 20mm gunpods, the MK108 30mm cannon, and the WGr21 A2A rocket.
I'm not unhappy with how it is, because having any other type of armament available in the game, would depart a certain amount of realism from the real game. Ofcourse, AH isn't WW2 per se, but IMO it needs a certain level of represantativeness when it comes to depicting WW2 aircraft. Departing from that standard calls out for abuse only, and I've seen it happening in IL2/FB.
I do understand why people would ask such a thing, but IMO, they shouldn't.