nooby,
Your logic is a bit flawed, the amount of power that is in the 139 is far beyond the needs of a full Cat A from a rig. As the PM on the S92, I was intimately aware of the JAR OPS needs, and several helos meet full Cat A from rigs at weights that allow good payloads and good range. The 139 carries even more power, to the detrement of its payload at even medium ranges.
Note that the 15000 lb 139 has the same power (2 x 2000 HP engines) installed as the 21500 lb Black Hawk.