I wanna note that while "derangement" is a pretty goddamn strong language, the gameplay manifestation really depends on how punishing QM wants to play it. It could take a shape of comparatively reasonable compulsive habits, or it could be straight up ruinous nonsense. Consult Your QM™ . Bottom line, a derangement usually could be suppressed for a scene at a cost of 1 WP, but if you got a bunch that proc reasonably often, that could get pretty expensive.
That said, 5 dots charm for a +1 aspect is not particularly efficient. This seems to be more of "charm as worldbuilding" rather than "charms as a toolkit" element; a nod toward how Lunars could turn into insane monstrous shoggoths back in the age of legends, rather than something that provides actual mechanically-relevant tools to the players.
I also gotta note that I can't really say that Lunar excellency is that much worse than Lydia's, mostly because attribute-boosting is a lot more flexible and somewhat more xp-efficient than WP-boosting. WP 10 + WP regen trick required a pretty major investment.
...IIRC, there also were some non-fleshcrafting tricks for attribute-boosting Lunars into the stratosphere, but I can't find them on a quick rulebook skim, so IDK.