http://www.youtube.com/watch?v=ndZoP4yctqA
This video is from early 2009 which is before:
-Degreaser
-Airblast buffs
-Crit flares
I know that most of those clips are from pubs, but it just shows that it was still very possible to do the things back then that pyros do now, you just actually had to be good at it. I'm not saying the degreaser and pyro need nerfs, but anyone who thinks that the pyro NEEDS the things listed above to be relevant compared to the other classes is objectively wrong.