Most of the time anything electronic runs hot it runs less efficiently than it would at a lower temperature. I would expect to get less brake out of a motor that was 190 degrees than one that was at 110 degrees.
Running your motor right at the temp shut down threshold over prolonged periods of time can cause even sintered rotors to degrade and it might be in your best interest to look into replacing the rotor more regularly or backing down on your gearing so that that those temperatures aren't reached.