Hello,
Regard to power consumption there is no much different between Soft and Full MAC in 1273.
In 1273 the FW is taking care for the power management and wake-up the host processor only when needed. for example scan connection is taking care by the FW and we added data filtering mechanism to do initial sort before waking up the host.
The architecture was chosen carefully so the host will be interrupted only on rare management frames while more frequent control frames are handled by the device (FW).
regards,
Eran