Hmmm... Why are the MB and DUCs are disabled...? Chances are the discussions must be buried in those 30+ page threads which I have neither the time nor courage to read, but I don't recall anybody ever complaining about them being overpowered, although I've heard they're nice early-game weapons.
They are all disabled because it makes ship combat more interesting... And ships design more interesting. Forces players to build ships they normally do not build...