What I hear is two divers not really listening to each other. Thalassamania has a huge amount of experience, and started diving even before I did by about four years. But at the same time, iPutty is making some interesting points.
Buoyancy control has been an issue for many, many years. I have written on that topic, and hope to post some of that here (I'll see if this will take PDF formated documents). It will, but may not have enough memory to do much (400 KB, but PSD documents have a 1.5 MB limit). Anyway, it doesn't look like an entire document can be scanned and put up here.
We have been either adding air to something, or subtracting weights, for the entire time I've been diving. So there has been attention in cold water to buoyancy control issues. Concerning the wet suit materials, I really don't know what today's suits do as my last one bought that I'm still repairing and using is about 12 years old, when they were still 1/4 inch. I have another (which I currently do not fit into) that is from the 1980s. Having a less-compressible wet suit would probably mean starting out with less initial weighting to be lost, as the suit's buoyancy would not be as great. This would make vintage compensation with only a weight belt easier. It could also be that when the switch to mm instead of inches was made, we got a slightly thicker wet suit. According to Google, (1/4) inch = 6.35 millimeters; I believe in cold water we are now getting
8 mm wet suits, which would be 0.32 inches (5/16 inch). So this may be where some of the extra buoyancy is coming from (more of those closed cells).
Having a compressed neoprene may sound like a great idea for buoyancy control and toughness, but it may also come at a price of less protection from cold. It is those gas cells which protect, and this is best in shallow water. Wet suits become much less effective in deeper depths, due to this compression.
SeaRat