TMac isn't a bad coach. He's just an average coach. Not good, not bad. I have my criticisms of him, but every coach has their blind spots.
With that being said, you do get to a point, with any coach (even the great ones), where a team needs to hear a new voice.
The Kings are spending 81M+ on this roster. They made a big trade in the off season and signed Fiala to a big contract. When you do that, you're expecting the playoffs. If this team starts to fall out of the playoff picture, it will be interesting to see what Blake does. Hopefully nothing reckless.
When GM's become short term focused, bad things start to happen.