If you're interested, you can see the provisional rules for maulers in
Borders of Madness here, as well as sample Squadron Scale Ship Cards for the
Klingon D6M and
Romulan Falcon.
The main thing those playtest rules are missing from the
SFB version is the issue of shock. In
SFB, the inherent nature of the mauler cannon means that firing it causes a high degree of stress on its host unit, to the point that using it beyond a certain threshold risks damaging your own ship. By and large,
FC tries to avoid "shock effects" if it can; for example, the
SFB version of the
New Jersey battlecruiser runs the risk of shock if it fires more than four of its photons in the one turn, so the
FC version (and in
ACtA:SF) gets around that by simply not allowing it to fire more than four per turn. Since maulers can't get around the issue of shock so easily, allowing them to fly shock-free in
FC would risk creating an imbalance in their favour (since there'd be no penalty against using the mauler cannon as often as you liked).
Whather the playtest rules change much, if any, between now and the time if/when
Borders of Madness becomes a formal product remains to be seen; but in any case, I"m not too sure if it's a good idea to expect them to make it over here sooner rather than later (if they come over at all).