Ken,
Spanky's premise, with which I agree totally, is that once you use any significant amount of off-axis thrust vectoring, you slow down awfully quickly and become a strafe panel in the sky. This big thing here is that those engines in the prototype appear to produce so much thrust that energy loss isn't such a big problem and it appears to be able to accelerate rather well, even when pulling hard. In my opinion, the T-50 seems to offer the option of trading energy for extreme manoeuvre with the knowledge that you can regain it quickly, or it can do sustained, higher-energy, high g. Nice to have an option you don't have to use, but can without taking the rest of the day to get back up to fighting speed.