Yes, it's a shame they're not used more. On the other hand, some are actually quite hard to use... for example, Hustar 3 looks excellent, but once you use it for a level it quickly becomes apparent it's missing more or less essential stuff like 45° slopes.

Still, there's others in there that are unjustly neglected... That said, the one tileset I was talking about in my earlier post in this thread is actually based on Waz's sets.