I actually think on Stevens part this was not a great fit for him.
The Celtics are a glory franchise and it is tough to turn down that opportunity and money, but they are going to have some tumultuous years ahead as they rebuild.
I think as a rookie coach with no pro-experience he had a high threshold to meet with players anyway, and when you throw in the fact it is conceivable he may have 2-3 ugly years right off the bat it is not hard to envision a scenario in which he is getting tuned out in the same way we saw happen with Byron Scott in Cleveland because the losing just wears everyone down.
I could be wrong and it could work out great, but throwing a college coach into a rebuild that is not going to go over well with that fan base in the first place and I see a recipe for trouble once the bloom is off the rose a bit after the first year.
I think he is a great coach and has the potential to be a good NBA coach, but this is not the situation I would choose as this will change the entire trajectory of his career for better or worse. I just don't see how he is able to win big and succeed there in a timely fashion before they start turning on him.