If you are not doing extensive tempo to build your aerobic base how do you build your aerobic capacity? And please don't tell me sprints between 80% to 95% because that is NOT aerobic.
You talk about Dan Pfaff program. But don't forget Dan sprinters (i.e. DB, Surin, etc.) were already develop and in great shape. Plus those guys were 100m sprinters.
Finally, if 8x200m extensive tempo is too much volume for you then maybe you should go back to being a short sprinter. But then again, I don't know too many short sprinters that can't do 8x200m@70%
Not trying to bust your balls 400. Just keeping in real. Don't take it personal.
Btw, 3000m is usually the max for extensive temp, I gave you the minimum so not to scare you as you seem to be highly adverse to conditioning work!