I disagree - for now. Three games is way too small of a sample size, especially given that Kanter is being asked to change his game to fit Quin's system. I would continue to start Kanter for at least 15 games or so. I think it equally important to have a great player off the bench and Booker gives us that.
It's also super (like extremely important) not have a player that nerfs your entire offense and defense in the starting lineup.