Hello again. I want to talk about the other side of the gameplay experience for a moment. Cradle's assorted denizens are wildly inconsistent in threat level. Here are my thoughts on some monsters that I personally least enjoy dealing with, either because they're boring or force me to resort to strategies I find boring.
the inevitable Minis
I've already said my piece regarding compounds but I'll reiterate my points here. Despite being intended to spawn in large groups, and often infinitely, minis are durable and more individually threatening than most monsters.
I don't think they need much. Cut their health so that a couple Combuster swings takes care of a scarab in a full party (without damage bonus) or such, and make them guaranteed to flinch from damage as greavers do; glop drops in particular should move a lot slower when attacking. This should make them a lot more reasonable to deal with using weapons that aren't already good at everything because they can safely clear lots of enemies in wide areas (brandish, iron slug, nitronome, etc).
Punching Bags
This one's simple. Give wolvers, alpha wolvers, retrodes, and zombies some amount of tracking on their melee attacks again. Make them gain a little in T2 and a little more in T3, so they stay easy to deal with in T1. While we're at it, give knockers a little tracking, and maybe even a more threatening attack hitbox, as a treat. These enemies mostly just end up being fodder, with their static attacks being so easy to avoid, and despite removing tracking from those enemies (except knockers who were born lobotomized) OOO would not maintain this decision at all.
Some Fiends
Gorgos are possibly the most universally disliked normal enemy; certainly the one I most commonly hear complaints about. I don't think they're bad, in principle, being a sort of chimera of spookats and alpha wolvers, but their implementation leaves me with a burning desire to put every devilite into a car compactor so that none of them can be lazy enough to transform into a gorgo ever again. I digress.
Gorgos would be fine to deal with if their swaying movement was deterministic — especially because trying to hit a moving target with projectiles in this game is incredibly difficult due to the way the server handles them — and if their tracking angle was consistent and not very tight. Sometimes, I can run circles around gorgos and they make wide turns as they bite, struggling to keep up. Sometimes they make Initial D look like a straight line as they instantly swerve ninety degrees and put me in a world of hurt as I pass by. I have no idea why the tracking feels so random, or if it even is, but with how mobile they are they should not be able to track that well since it makes running away the only means of avoiding them. Also, amusingly, the rare "buttstomp" attack is far, far less threatening, and given that they need to be surrounded by players to use it, I do not think that was the intention.
As for devilites themselves, they feel like probably the most overtuned regular enemies in the game. While they, like greavers, can be interrupted by any damage, my experience is that their attacks come out too fast for me to actually hit them as a reaction. That is, if I interrupt them, then it's only because my weapon was already in motion. In groups they're kind of a nightmare. I'd just like if their attack windup was a bit slower, so that they feel more reactable. I admit this one is very much personal bias.
Devilites also have a handful of buggy interactions with promotion/demotion. Basically they should just check if they're dead before they try to promote/demote. I'm genuinely surprised that they don't and it leads to frustrating situations where devilites, mid-death animation, will suddenly revive.
Lichens
You already know what this is about. It's the spin attack. The one that comes out fast, is difficult to interrupt, and is threatening at all ranges. The bane of DaN farmers. Basically the problem is just that there's no safe way to plan around or react to this attack, as the spikes fly in random directions. Putting down telegraphs for where they'll shoot or making them shoot in a fixed pattern would do nicely.
Projectile Reactions
This one's probably because it essentially has to do with enemy behaviors that are easy to deal with in isolation but become a real dent in the experience in mobs. Mechaknights will (almost) always block incoming projectiles, making them invulnerable for a couple seconds, and in T3 they can do this pretty rapidly. A single mechaknight is easy to deal with, since you can bait out an attack and then nail them with the large bullet of choice while they're mid-animation. But as soon as there's a bunch of mechaknights, it's difficult to do that since they can essentially form a rotating phalanx and really bogging down fights if you're using something like Magnus or Brandish charges (compared to Autoguns or Alchemers that will safely chew through a single knight and freeze up its buddies, or bombs which plow through all of them without making a projectile to block).
The other concern in this category is wolvers. In T3 wolvers will burrow (ie teleport) randomly and also on reaction to projectiles. Unlike most enemies, wolvers do not react to incoming projectiles: they react to all projectiles. And, with seemingly no cooldown on teleporting, wolvers will just teleport constantly. They also can teleport while frozen, which feels wrong considering freeze is supposed to prevent moving. Plus, with tracking, wolvers shouldn't need to rapidly teleport to be relevant as threats. I'd make them only react to bullets actually shot at them, as mechaknights and gremlins, and put a cooldown on teleporting.
Neither of these enemies are difficult to deal with, especially if I just don't shoot any projectiles, but they still turn fights into a slog because they spam their projectile countermeasure and there aren't any ways to outplay a horde of them except to not use projectiles.
I like these suggestions, but how about we use this opportunity to try and kill two birds with one stone? Instead of tying certain enemy AI behavior changes to the depth, why not difficulty?
Elite has always been a bane of this game's weapon balance. The game was originally balanced around Advanced health/damage scaling and yet once elite became the playerbase's default, many weapons just ceased to function in the way they were previously intended such as many heavy weapons no longer dealing enough damage to reach the hit-to-kill thresholds they were designed around. Let's lower elite health/damage scaling back down to advanced and replace that "lost difficulty" with some of these AI changes.
In their current state, I find minis outright unfun so your suggested changes to them would remain universal instead of only applying to sub-elite. The tracking would fit wonderfully as difficulty scaling changes, though. I think it'd be a bad idea to give enemies a whole 360° range but something like 120° might be good on elite.
One of the least threatening enemies in the game are skeletons. They seem designed to be a "horde" mob, but even in hordes they're just walking crown dispensers rather than a real threat. Maybe on higher difficulties they become more "feral" and get faster to the point of a jog? Think of greaver hordes but with less insane mobility; something that can actually be reacted to rather than mandating proactive play (or just being outright unfair if you don't have the right equipment). Those bomb skellies actually achieve this decently well but I find them more annoying than fun on account of not actually being designed to be fought but rather to just be avoided (they literally kill themselves faster than you can kill them).
To be clear I think most of your enemy "nerfs" are overall benefits for the game so I'd apply most of them to all difficulties rather than just implementing them for Normal/Advanced only.