The question seems to be an interesting staple on the matter of MGE's lore, it is often discussed. And often, these discussions end in embroiled arguments with vitriolic fervor despite the context of the setting being a lighthearted fetish hentai. There is an irony here somwhere... I think this has alot to do with readers interpreting MGE in many different ways, we accept and fail to accept certain fetishes depending on our tastes, we find certain lorebits interesting depending on what our interests are, and we vary on how deep we read into the setting. We take all this and correlate it with what we deem as objective morality, and I feel this is where the animosity spawns from(combined with a sentiment of taking this hentai a bit too seriously). What line do we draw on what is objective immorality?
Really, the dark aspects of MGE can vary depending on who you ask.
Personaly, if I really pieced together the lore and imagined a world as portrayed by works both fan and official I'd probably find some things that rub me the wrong way.
Off the top of my head is the predator/prey dichotomy, alot of monsters are portrayed as predators that prey on men of course. The predator behaviour comes off as malicious, selfish, a domineering assertion of superiority over us inferior and puny lifeforms. Now yes, granted, not all Monsters will prey or torment men into submission, but a great number have little regard for your say on the matter. There is a level of contempt here that irks me, and I still feel dirty about it despite the undying love and affection that even the most cruel and sneering of monsters are supposed to show you that washes any fear or hatred away. Mamono are to be loved but also feared at the same time. It does not feel right, it feels more as how someone would love a pet, or a Roman master would love his slave. A distinct lack of respect in this relationship, a constant belittlement and practically abusive manner that is some how supposed to prosper. I understand that a monster, no matter who, gives an undying loyalty and affection to her husband. But to do so via browbeating and bullying her target into matrimony really sours the pallette.
OOC-wise perhaps it is a fetish thing that I'm simply not comprehending here? Perhaps my fetishes just don't line up to this line of kink? But from an IC perspective I'd be horrified at this, especially because of the fact that not only are humans preyed upon, they have practically no means of fighting back. Human not just prey, they are defenseless prey. Monsters are faster, stronger, at times smarter, virtually immune to fatigue, disease, and starvation, practically anything a human can do, a monster do better. I don't know about others, but I certainly would not want want to live in a world where I couldn't walk to my local gas station without getting accosted, bullied, or outright assaulted, and there is nothing I can do to defend myself. The only things that can potentially avoid this is either a miracle, or finding a wife. Then you'll only get regularly assaulted, bullied, accosted, but perhaps then you can run home and tell your monster wife to defend you. Is that what is in store for humans/incubi? I wouldn't want to live in a world where my kind *as a species* is the quivering lower lip of it, cowering under the might and mercy of monsters while hiding behind them as they fight for us.
This is on a different topic and I'm rambling here, but if I were to do anything for the setting I'd change it to balance the 'power gap' between monsters and men. Or at least allow somebody in the setting, be it the Demon Lord, the Order, or anyone else strive toward this parity. You could say maybe the DL through Incubi, but I haven't really seen anything detailing the 'New Human' to adopt a monster's power. Only the lengthening of lifespan, disease immunization, sexual prowess, etc.
Ignoring the IC lore and such, at least through this, there is at least some humans that can defend themselves that dont have to be one-in-a-million badass heros blessed by the gods. There are still weak humans, but now there can be strong humans(or elves). Let the average man-warrior be on par with the average mamono-warrior, a 50/50 chance and anybody's game. Mamono still 'hunt' men, but there is also an intrinsic respect between man and monster, for they are each other's most dangerous game.
Before anybody J'accuses me though, this isn't anything about the Order. If anything, I'd say the Order would lose control of their fearmongering narrative after humans see Mamono as less and less of a threat. Its honestly just about removing the curbstomp.
But hey, thats just me and my two cents.