i disagree completely that anything needs to be done to mitigate mood breaks. They ARE the punishment for low mood in the video game setting.
Pawns SPECIFICALLY can go berserk while attempting to be arrested during mental break. It was added for an important reason, and is almost certain not to be removed.
Additionally, nonlethal subduing has been suggested to death and there has never been even a hint of it being added. Pretty much every mod that has tried to introduce it basically ends up giving a "perfect" system for free pawn recruitment in raids, since you're not meant to be able to take down hostile pawns nonlethally.
The ONLY concession i see you maybe being able to get towards this suggestion is possibly, eventually allowing high social pawns to cheer up pawns (not IN a mental break, but before they happen, as a preventative measure...once the mental break hits, you're not just going to get a risk free end to it, the mental break is the punishment mechanic)...but even that is unlikely, since the current (basic, but likely to be expanded) social system and the "kind" trait already does that.