I think it has more to do with play style. The way Giannis relies on his physical attributes instead of his skills, he is very easy to shut down come playoff time. Sure, nobody is going to put their body through the type of abuse that players like Shaq handed out during the regular season, but the playoffs is a different story. Until Giannis learns to add more jumpshooting and passing to his arsenal, I don't see him ever being able to win a championship. With the long term moves the Bucks are making to surround with what I would call less than ideal surroundings, I wouldn't be surprised if Giannis was forced to change teams to have a chance at a title.
You are absolutely correct, Giannis downside is really in the playoffs and I don't understand why the coaching staff is not yet replace when they failed 2 season already. Bucks (Giannis) are hype in the regular season, but things changes in playoffs and they have been so predictable in the past 2 seasons already. I guess Bucks has to follow the Nets, instead of maintaining one star, why not add 1 more or 2.
He was really check by teams in the playoffs, no more long strides to the basketball for easy layup or a dunk. They made a few chances this season, but it's not enough in my opinion. And now that Nets is the favorite, I'm not seeing the Bucks going to the finals this year. Giannis will be again check and there's no one to take the scoring, maybe Middleton but he is inconsistent.