I am hard pressed to think of an instance where initial hard controlled braking to avoid a sudden oncoming obstacle is a bad idea so I believe the OP was right on. You can let off the brakes and swerve at a slower speed if time / conditions permit. When I am closing with an opposing obstacle the potential impact energy is determined by the SUM of both our speeds. If I get rear ended the far less energy state will be determined by the DIFFERENCE between our two speeds. I will take the reduced energy of a Difference over a Sum every time.
That said I always enter a blind curve from as far outside as possible thanks to reading Proficient Motorcycling http://www.amazon.com/Proficient-Mot.../dp/1889540536
, Ride Hard Ride Smart / How to Ride a Motorcycle by Pat Hahn as well as several other safe biking books. I have not yet mastered Hough's early braking / roll on the throttle on exit strategy but I try. I also try not to over ride my sight line keeping at an absolute minimum a 4 second sight line (unlike the far majority of cyclists) and I try to stay at or below the speed limit. Finally, if someone is riding my tail I slow down and let them get by so being rear ended is far less likely for me. Perhaps these techniques are not quite as fun as riding fast into blind corners like a video game and always passing everyone. But then again, riding any motorcycle on just about any road gives so much pleasure compared to not riding that I can forgo the additional pleasure far riskier behavior brings.
The fact that the OP got down to about 5mph is a credit to his skills. Reading and practicing the skills in Proficient Motorcycling and Ride Hard Ride Smart will help him avoid the next "impossible" situation or at least reduce the severity like he did this time.