Originally Posted by
Triceron
The thing is the gap between 'high effort put into an NPC' and 'made playable' is quite significant.
NPCs only need to support a handful of armor designs and Blizzard can call it a day. Most unique NPC races like Sethrak or Naga aren't built to support 100% of the gear in the game, like helmets, backpieces, tabards etc. To get all that working even for a simple humanoid like an Ogre is a lot of effort. Just the presence of a forehead horn means they have to modify all helmet proportions to make fit, or else deal with a horn that will ultimately poke through.
Or with a Sethrak or Naga, all they have to do is make one model and leave the rest to slight color variations and that's about it. With a playable race, people are gonna expect a wealth of customization options like different hairstyles, different face textures, horn option, etc etc.
So yeah, they can affort putting a lot of effort into NPCs, and even give them some customization options to boot. Or even give them custom animations, like Sethraks with crazy long tails. But taking that step to making them playable would still add on hundreds of additional of man hours making tweaks and adding customization options that is usually not worth the effort unless they had a real good reason to.
The last time we saw this was with Kul Tiran, where they didn't plan on them being playable but made a last minute to (because they felt it necessary to balance out addition of Zandalari on Horde) and it still took them months after BFA was released to be added.