I find myself wondering about protection warriors as tanks. Clearly, we're neither the most nor least popular tanks, holding steady in the middle of the pack - both blood DK's and protection paladins absolutely own tank representation. Blood is at 4.2% and prot pallies at 4.1% of total class/spec representation in Throne of Thunder, with prot warriors at 2.7% and guardian druids in about the same spot as brewmaster monks, 2% for guardians and 1.8% for brewmasters.
It's fairly clear that fury warriors, despite being a relatively smaller fraction of total class representation, are by far the most popular warriors in current raiding. Protection is not only second, but a distant second, and arms (despite being a solid 3% of the total player base overall) is vanishingly under-represented in raiding. We'll worry about arms in raids later. For now let's ask why protection warriors aren't being seen in raids. It's not based on class popularity by itself - based on looking over Realmpop for a couple of hours I'd argue that warriors are holding pretty steady at about 9.6% of the total population. (It's a slight drop from the 10.14% we saw last December) World of Wargraphs puts the number at about 9.5%, so either way, there are a lot of warriors. But looking at the Wargraphs data, two things come to mind.