My problem with the placement of the left analog stick on the playstation controllers doesn't have to do with the stick it's self, but more with the D-Pad.
This was never a problem on the psx, and wasn't that much of a problem with the ps2 except for a couple of cases, but for any game that requires you to use both the control stick and the d-pad for different things, it makes the game less fluid.
Two cases i'll point out, and they're popular ones: Mass effect and Kingdom hearts. Both of these games use the control stick for movement, but also use the d-pad for various features. In kingdom hearts, when i had to use an item, i would have to stop moving completely, usually taking hits in the process. this could have been avoided many times with a gamecube or 360 controller. with a center placed D-pad, i can reach over with my right thumb and go through the functional d-pad keys, while still remaining mobile. I did this in both mass effects, and it works ever so nicely. it would be hard to work your hand clear over to the other side of the controller to use the d-pad on a playstation controller.
If you need to move, aim, and use the d-pad at the same time, i'm pretty sure you're screwed in no matter what controller you're using.