Regarding crown of madness, it eats up your concentration, your action, and the target can save at the end of any turn. Moreover, even though you direct the subject's attacks, the spell does not state you can direct their movement, so it seems legal for the victim to just move away from its allies after the first round of combat,
This is not in the letter or the spirit of the spell at all. It is for mind-controlling one of the opponents to temporarily turn them against the rest of their group. The victim of the spell is an ally, and allies do not bail out when their friends are in danger.
Interpreting the spell like that is shady. I'd even call it nonsensical. [EDIT: I was wrong. See my reply later in the thread.]
and considering that monsters commonly have weak ranged attacks, now this spell becomes just a poor man's hold person. It will generally be better than hold person only when facing more than one enemy, and you can target an enemy who has a better offensive capability than yourself, including ranged.
Yeah - here's what it is in game terms:
At the very worst, it's Hold Person. If the spellcaster needs to use their action on something else - like, say, healing a team member - then the enemy does nothing, to preserve the action economy.
Mechanically, the opponents have one less member attacking the party while the spell goes on. Just like a hold person. So far so good. Huge, in game terms, with the action economy.
Additionally, (and why it's a higher level spell), the opponents have to either attack or attempt to subdue a member of their own party - which means they're taking additional actions away from fighting the party on their own person. Or, they eat attacks and damage from one of their own, which is draining their hit points faster than expected. Or, the member of their party who is being attacked has to use the full defense action to try to wait it out - again, taking away actions that could be used against the party.
The whole thing is a way to use the spellcaster's action to soak at least 1 action from the enemies. If they're lucky, it also includes extra hit point damage, or soaking additional actions, or sowing chaos in their ranks.
So, seen that way, the entire thing is all about taking a several-round advantage in the action economy.
Adding an interpretation that a mind-controlled character who will literally attack their own team members is in such a state of control of themselves that they just walk away to prevent it from happening is bad faith metagaming. [EDIT: I was wrong. See my reply later in the thread.]