You are very knowledgeable about beekeeping and helped me a lot in my early years with advise but you shouldn't be closed mind about other peoples experiences. I now have 12 years under my belt and have gained a lot of local experience that just isn't yours. You are starting to sound like a Roger . My wood colony's are also dry as a bone unlike the poly and we have had 2 inches of snow and -5c this weekend and they are running about under the polycarb crown boards on all my wood hives. Before the snow this week they were still bringing in 2 types of pollen, Ivy and Hazel by the look of it. This is not a competition, I think it would be a benefit to figure out why we have such different experiences rather than nail our colours to a mast based on just our own experiences and support of just one supplier of preference. Beekeepers about 5 miles from me who are very prominent in the BBKA moved to complete poly hives a few years ago and I respect their choice but there is a huge difference between their location and mine which can be a massive difference in determination of hive type. Emperors new clothes don't fit everyone.
I to would love to know why we are seeing such huge differences with the same hive type.
As I said in my last post damp may be the issue, if your poly hives are damp inside, as you keep telling us they are, then that may explain why you are seeing a slow spring build up. Logically poly hives are better insulated than wood so retain heat making brood rearing in spring more energetically efficient as, they don't lose the heat so fast. If the heat of a spring sun gets your bees flying in a wooden hive and not a poly then the difference in insulation is quite apparent.
But people should use whatever hive type works for them and not decry others choices. One good reason for wooden hives is when you have a rat problem. A mate of mine has had to move back to wooden hives due to a serious rat problem in a couple of his apiaries where they were eating the hives during the winter.