Master skins were cool. Earning them was also cool.

However some of them we could have done better with their visual design. Since switching over to the new progression system we've found that the quality of our skins have been better because we have been able to develop multiple cool themes during the concept stage. We are able to pick the concept that's the coolest and go. It also allows us to have a more fluid way of creating. If we have an idea we can point at a hero and say this would be perfect for them instead of looking at that same hero and try to come up with a skin for them. That works too but sometimes can be harder in the brainstorm sessions. Coming up with the next level Arthas has always been a challenge. How can you improve on the Lich King? (In before Arthas remodel when? Blizz plz) Master skins are cool ideas. They work great for heroes like Zul'jin or Xul. Sometimes putting out a ton of skins that are just ok isn't a good use of our resources. We would rather put out the best skins we can.

I think there's room to explore a Hero's own fantasy in future skins but it's unlikely we'll go back to a progression based Master skin system again. The idea of course is to have the ability to earn future skins through simply playing the game or buying them with gems if you choose to.