one of the few rare case of bestial race popular in mmorpg, is the worgen, but two reason at this:
- 1) they can be human when not in fight!
- 2) werewolf stay one of the favorite monster race know.

let's be honest most of the time the bestial race are underplayed... or are played, because people don't have the choice. let's take the race from World of Warcraft...
before they did had added the blood elf, most player was playing undead and orc... but when the blood elf did come out, a tons of player did change of race. why that? because most player prefer play cute race than bestial race. a lot of them can't immerse themself if them avatar is too far from themself. that why most of the time, race Humanoid (and not human) are the one used.

you can argue all days, bestial race are often (actually most of the time) the less played. add a new race that will be played by only a small part of the community is a loss... and i did explain already that add this sort of race, will ask a lot of ressource and investement, they can't decide this sort of thing, without be sure it will appeal the player. because add a race serve to appeal to more player... not to a minority. it's a huge argument for sell an expansion into a mmorpg.