As soon as this team was formed, it was obvious Spoelstra was in a no-win situation. If they won 75 games, he would get no credit, it was simply the greatest team ever assembled. And if they struggled, he would be the first blamed.
But at this point, they really can't make a coaching change. I personally don't think Riley wants any part of coaching them (atleast not this season), because if they lose, he will then have nobody to blame but himself.