I never thought he was the right coach for this team, but the Cavs had already signed him by the time LeBron decided to return, so they had no choice but to see how it will plays out.
A team like the Cavs needed a gritty competent defensive-minded head coach. A coach who isn't afraid to call out LeBron for playing lazy on both ends, etc. It was always going to be hard to find that coach. It seems like the only head coach that LeBron has total respect for is, Gregg Popovich. You have to be a proven winner at the NBA level in order for LeBron to respect you.
I don't think he ever liked Spoelstra, but he knew that Spo was Riley's right hand man and Riley is a proven winner, so eventually they won two titles together. So far, Blatt looks like a novice at the NBA level. The Cavs have won games solely because LeBron, Love, and Irving are carrying the team. Blatt is so dependent on LeBron to run the offense, you can see the desperation on his face whenever LeBron sits on the bench and the team starts playing inconsistent on every end.