The issue isn't whether the motor is sensored or sensorless in terms of power output. Aveox made some very powerful sensored motors when they were still in the RC game.

The problem is that motors like the HV4.5 and HV6.5 appear to be based loosely on their little brothers (ROAR legal motors, which have design constraints). These ROAR designs seem to be pretty power limiting (I don't know if that's because of the iron stator, wind type, or rotor size, or perhaps a combination of these three or even more variables; their tiny rotors don't exactly help with torque output though).

The best option I've seen so far is hybrid systems in terms of sensored vs. sensorless. I believe the Mamba Max Pro will be doing something like this, and ESCs like the Speed Passion GT ESC also use this. This way, you get the best of both worlds (low speed driveability and cog free operation, coupled with variable timing once the motor gets going that is associated with sensorless systems).