Stardard Sleep is suboptimal, we know, but, lets see again.Charm person during combat is highly unlikely to work all that well even at disadvantage.
You're blowing a 4th level spell on 1 opponent and doing a maximum of 10d6 (assuming they all hit) to 1 opponent - well ok.
By 7th level sleep is highly suboptimal - you probably swapped it out for something else!
16 AC by 7th level? If the monster is rushing you, he'll probably hit that most of the time - even at disadvantage. Remember, you can't cast shield.
Sure, 3rd level spell - decent resource cost and situational if your already in the middle of a fight.
Another HUGE resource cost - 4th level spell.
How are you quickening a 4th level spell with 2 spell points?
Or did you not bother with the darkness this time - but then you're now out spell points, can't cast and REALLY reliant on concentration saves (the giant ape bit is usually better on others so there isn't a con save EVERY time they get hit).
Again, interesting schtick, can certainly see trying it - but it's not insane.
With PAM+Warcaster combo, it's 100% chance of working. You reduce the enemy's hp with Spell Oportunity attack and then, sleep him. (humanoids).
A level 4 Sleep is average 58 HP. It's 100% nice your damage from Spell Oportunity attack.
a standard fighter level 7 has average 60 HP. Reducing 20 or more with your spell oportunity attack is 100% chance of sleep works against it. The fight is over.
Remember that Sorcerer can swap spells slots for sorcery points.
Fear isn't a level 4 spell slot.
Darkness 2 sp that you regain instantly with flexible casting.
so, you have 7 SP free.
Quickening to turn into a Giant Ape + The Hound is just too powerful.
That premisse is bad because works for all spellcasters. Every leveled spell has a cost.