Fix 5E Fights By Turning Monsters into Glass Cannon Puzzles

I’ll skip the whole preamble establishing how fights in 5E and other modern-style D&D games are too long. Let’s go right to a solution.

The recipe for a glass cannon puzzle monster is as follows: 

• Reduce the HP by a lot. If you like to math this out, you want the total monster HP to be equal to no more than three rounds worth of the party’s total DPS. Probably closer to two rounds. But if you don’t enjoy that math, just eyeball it.
• Make their attacks 25-50% stronger. They are going to get fewer chances to hit, so they should hit harder. You can buff their to-hit somewhat as well, but I don’t find this to be necessary. They should hit hard enough that the first time a PC takes damage, the group should be a bit surprised and taken aback.
• Give them a big edge. Some monsters already have these as they are currently written, but they’re often narrow, superfluous, or transparently obvious to overcome. Give more monsters powers that make them hard to overcome… at least to start.
• Tie that edge to a major weakness. They have some kind of weakness, usually associated with their strength. If understood and exploited, they become much easier to defeat.

1d10 OK give me some examples: 

1. The azer’s heated body and weapons can set creatures and objects on fire, causing them to burn and take damage each turn. The flames can spread to other creatures and objects. An azer who take cold damage or is doused in water loses these abilities until they complete a long rest.
2. If the banshee sees its reflection, all of its immunities and resistances drop away, and it is as vulnerable to damage as a normal person. 
3. The chimera is immune to fire (from its dragon head), fear (from its lion head), and losing its balance (from its goat head). But the heads hate each other. Make a cromulent criticism of a chimera head, even in the midst of a fight, and it loses the attack and immunity associated with that head until the end of its next turn, as the heads bicker and undercut each other.
4. The duergars’ ability to enlarge themselves and turn invisible make them fearsome foes in combat. They have resistance to damage from creatures who are smaller than them or can’t see them. But when fighting creatures who are larger than them and/or that they cannot see, the duergar have disadvantage on morale checks and Wisdom saving throws.
5. The distracting sound of the hook horror’s claws scraping against the rocks of the Underdark requires any spellcaster to pass a concentration check in order to cast a spell. The hook horror has disadvantage on saving throws and vulnerability to damage from any effect with an auditory components (e.g., Tasha’s Hideous Laughter). 
6. The peryton goes directly for the heart. If it succeeds on an attack roll on a dive attack, it is an automatic critical hit, and if the damage leaves the target at or below 0 HP, they must immediately make a death saving throw, or the peryton rips out their heart. The peryton will then attempt to retreat, taking the heart with it. Some resurrection magic will not work without an intact heart. A peryton that has damaged a humanoid but failed to rip out its heart is blinded by single-mindedness and has disadvantage on Dexterity saving throws and attack rolls against other targets until it has killed the wounded target. 
7. Shadows are fully invisible in darkness, torchlight, and even magical light. They are visible and completely susceptible to damage in candlelight.
8. Skeletons are almost completely immune to piercing and slashing weapons, but can typically be destroyed with one hit with bludgeoning weapons.
9. The sphinx can't be harmed until you answer their riddle. If you stump the sphinx with your own riddle, it is vulnerable to damage you deal until it can solve your riddle.
10. The troglodyte’s stench doesn’t only poison those near it, but incapacitates them as well, if they fail their saving throw by 5 or more. But the troglodyte’s aversion isn’t limited to just sunlight; soap, running water, or anything else that could dilute or cleanse its stench forces disadvantage on its attacks and Wisdom (perception) ability checks.