I had a little trouble editing the quote, but this bears repeating.
In my mind, I make the distinction between small-w wbs and large-w WBs, with the latter being the purpose-bred for generations sport horse. Small-w wbs are harder to define because they are diverse – draft crosses, QH crossed with WB, etc. And there are some breeders of small-w wbs who are following the ISH route of starting with heavy draft mares in F0, but gradually adding more TBs and other sport horses (including big-W WBs). After some generations of this, my guess is that they will have something equivalent to a WB. And it may have a lot of WB in its pedigree.
I think folks should also consider the effect of human history on horse breeding, especially in 20th century Europe. The early to mid 20th century WBs were more drafty and heavier, but as the need for “utility” horses disappeared, it made sense to breed a finer horse more suitable for riding. Then you have the chaos of WW1 and WW2, loss of breeding stock etc. so probably a trip back to heavier mares again, assuming that is what survived the Wars. The omid-century/post WW2 WBs are indeed quite heavy horse.