The Watcher itself is not really the issue, balance wise yes mowkai has been powercreeped into oblivion but mill was never a top tier deck. The problem with the Watcher in my opinion stems from cards that let you cheat out units (spektral maiden, intimidating roar). Watcher should not be able to attack until the cost reduction is fullfiled, freljord is already good at stalling and ramping. The condition was a way to play around Watcher, losing turn 7 to double ice pillar spectral maiden into watcher is just stupid.