Brother MacLaren said:
Most of the designers on 3E weren't around to "learn from their mistakes" for 3.5. Some of them still prefer 3E to 3.5 and don't regard the 3E design decisions as "mistakes."
Considering the size of the development team and the fact that different players prefer different styles, I don't find that surprising. That said:
Jonathan Tweet: No longer plays 3e, working on 4e
Monte Cook: Stopped using 3e and wrote several new variants on it (AU, WoD, etc.)
Skip Williams: Unknown, but worked on 3.5e
Rich Baker: Working on 4e
Bill Slaviscek: Working on 4e
David Noonan: Working on 4e
Andy Collins: Working on 4e
Bruce Cordell: Working on 4e
Rob Heinsoo: Working on 4e
I mean, when I look at
this list of 3.0 contibutors and compare it with
this list, I'm seeing a LOT of duplication. I'm not trying to say that some of the folks who worked on 3e and 3.5e aren't thrilled with the direction, but a large number of the R&D department has maintained continuity. Folks like Sean K. Reynolds, JD Wilker and others certainly weren't thrilled with 3.5...but they also all have released their own changes to 3.0 in the intervening years based on their experiences and personal preferences. So I suspect that, like any group project, there were compromises made and each designer views certain aspects of any edition as having flaws they'd like to address.