The intriguing twists on the fairy tales were a great idea, but Ludwig Kakumei has one of the least likeable casts I've seen in a while. Ludwig is an arrogant inconsiderate jerk who spends all his time chasing after beautiful women (who most of the time don't care one whit about him) while treating his nearest and dearest like c-ap. Which would have been fine, if the guy were a true sadist instead of a "fantasy sadist" (ie: a handsome, charismatic man who for some reason is nasty and inconsiderate only to other men, ugly women, and old people; pretty women, of course, are treated like royalty). His devoted servants/slaves Wilhelm and Grunhilda are masochists who repeatedly risk their lives for a guy who always either abuses or ignores them; all the "princesses" (with the exception of Ludwig's One True Love) are either cruel conniving bi---es or sweet, vapid wastes of space; all the "princes" are either cold-blooded bas---ds or spineless air-heads. The only character I enjoyed was Ludwig's mother (women who have all the men by the b-lls through any way other than sex get a big thumbs-up from me), but she was absent for most of the series.
Now, none of these things would have been a big deal if this were a manga where the characters are merely an excuse and the plot's the only important thing. But Ludwig Kakumei is a story with drama, romance, comedy and tragedy at its core. If those four genre are to be successful, the cast has to appeal to my heart. And it didn't.
But the most annoying feature, imo, was the shift in the tone of the plot. It went from being genuinely dark and foreboding to being a half-heartedly dramatic comedy full of absurd situations where everyone is a moron and the Only Sane Man, Ludwig, has to swoop in and save them from their own stupidity. Accordingly, Ludwig himself went from being a true anti-hero to being a "funny" anti-hero, thereby losing the only quality that made him appealing to me. And the way he fell in love (with a woman he spoke barely four or five sentences with and never properly met) was boring, cliché and completely unsuited to his personality.
None of these are things I made up, either: Kaori Yuki herself mentioned them in the author's notes for the 4th volume.
So, in the end: 8/10 for the plot, but I'm deducting points for 2-D characterisation and the unnecessary mood-shift.