Yeah, exposed center pins is a very dumb move. Not as stupid as having exposed pins on the tube amp PSU but it is up there. A teflon jack like this from China would cost next to nothing and probably be cheaper than the WPI's...
As for the transformers, I sent the Lundahl boxes off for powdercoating today. I resisted the urge to do them bright red or something like that...
The 1.5um diaphragm was introduced in 1997 so that's nothing new. I think this is just the old model or did you contact them?