I see what you're saying, but when you look at the numbers, there's plenty to be excited about if you're a TWolves fan.
Though they may have only won 31 games, their Pythagorean win total was 38 based on ORating minus DRating. Their SRS was -.64, something you don't see from 12th seeds very often. They blew 27 second half leads last year, many of them double digit ones. They easily could have won 40 games with a very young team. They now add a very good second half player and closer in Butler to help them maintain those leads. In addition, their peak play was very good as they could beat down many different teams in the league and compete with every one of the best teams when playing well and that's WITHOUT Butler and with a negative black hole player like Lavine who played no defense at all. That peak play ceiling just got higher.
But mostly, people undervalue how good Butler was and how bad the rest of the Bulls were. With him on court, they were a 50 win type of team and with him off court, they were a top 3 lotto type of team. He spent most of the season in the top 5 of RPM and was a top 5 two way force all season.
Towns is going to get better. He's already one of the most offensively skilled big men perhaps ever in the league and needs to improve defensively as he was trash on that end last year. One more year of Thibs and a defensive leader like Butler will help accelerate that growth.
Wiggins can now concentrate even more on defense and perhaps make progress in that area. With Butler on court, the opposition's defensive focus won't be on him. He, too, can make a leap this year.
Their issue is going to be shooting and how well they progress defensively. The defense will improve for sure. Not sure how they'll address the shooting. I can see them winning 50+ games and being a team nobody would want to play in a series.