I think the important thing to consider here is what's the same about both arguments in terms of "taming" and lowering his power level. Why did Buu get stronger when Evil Buu ate Good Buu? IMO, Good Buu restricted the maximum output of power level because of his good nature. When Evil Buu ate Good Buu, he was then able to maximize his full potential and didn't have those limitations in place anymore. They both had the same potential for power, which is why Fat Buu was constantly underestimated and never beaten. When Fat Buu got mad, his limitations were taken off.
From there, Super Buu was essentially evil with lesser restrictions in place. Now you can argue this both ways, but nobody knows whether Super Buu still had limitations on his PL in place or not.
It's undeniable that Kid Buu had zero restrictions in place, and I think that's why the Kai's made these comments about him. Someone holding a machine gun with no fingers is much less dangerous than someone holding a baseball batt that wants to kill you by any means necessary.
Super Buu might've had the greater arsenal, maybe, but he stopped himself from using it BECAUSE he had skilled fighters who enjoyed equal fights and good sportsmanship.
Kid Buu might've had a weaker arsenal, maybe, but he was willing to use it all the time every time on anything to its fullest extent.
So that's what I think as far as power level and being "tame" goes. It can be argued both ways since we don't know how restricted Super Buu was, if at all. But either way, Super Buu was more reserved in his nature and wasn't ready to kill the planet since he loved fighting and wanted to test himself.
When he had no experienced fighters in his body, he didn't care about good sportsmanship, and he just wanted to destroy everything.
I would argue Kid Buu should regenerate stamina slightly faster and all of his Ki attacks should be at maximum power. Balancing obviously matters. But anyhow, making him stronger is the right way to go regardless of how it's done.
EDIT: By the way, some good advice: The only way to get the best of an argument is to avoid it.
You don't gain anything by arguing here. You'll be better off finding a compromise and moving on with your lives.