On a totally unrelated note: This apparent ubiquitousness of pee valves is something I wasn't aware of before I started reading SB. Around here, where virtually everyone dives dry, I've never seen one of those.
Yes, I totally see the point for tec divers who might spend several hours underwater, but for a rec drysuit diver? I can't remember one single outing where anyone has given a planned bottom time of more than an hour. Even I, who's a bit bothered with immersion diuresis, can hold it for about an hour if I remember to take a leak before zipping up and splashing. That's what front zips are for, right?