Maybe not "failures" (although getting a season cut and then cancelled probably makes you some kind of failure) but Sunrise's Valvrave and Cross Ange can be pretty much described as a hot mess or fun trash.
Valvrave is beautifully animated, has a fantastic voice cast enjoying themselves and loving the characters, and very nearly some deep messages. They even manage to do non-jarring CGI in a period where most CGI was pretty noticeable. It's general premise is a simple but insane one - possessed space memory vampires pilot giant robots against the space Soviet Union. It has problems with tonal whiplash, can be incredibly silly in places but also gives a far more down to earth portrayal of kid gets in the cockpit of a robot and fights a war and the kids declare themselves a nation tropes. What really did them in and led us to the pretty disastrous second season (where they had to drop a lot of plot threads and rush everything to a close thanks to having their planned 3rd season cut) was a pretty pointless and out of place (although not totally un-foreshadowed and actually reasonable well handled) rape scene. It certainly didn't need to be there but it certainly wasn't as out of nowhere as a lot of people said and actually the idea of these vampires being able to feed using things like sex and losing control when hungry was well established even if not blatant. But, it was right before the finale, viewership nosedived, faith in the series was lost and season 2 was a rushed disaster meaning they never got the chance to deal with it and it was mostly ignored, making it seem even more out of place and the series was pretty much labelled trash with a big budget. It was actually a fascinating look at how one scene can totally change a series future. It only got into Super Robot Wars last year. It's that bad.
Cross Ange sota goes the other way. It sold itself as fanservicey trash. It never shies away from a fanservice shot and a skimpy outfit. And most people just write it off as such. And yet there's a solid, if a bit muddled, story under there about finding yourself and is almost, so very almost, feminist. The main cast are almost all powerful, badass women, with actual varying personalities and body types. Ersha is no less badass for being a mothering type, than the cold sniper who secretly loves shoujo and magical girls, or the flirty bitch or the spunky youngster (which is cool at a time when lots of Strong Female Characters needed to be a cold, emotionless and unfeminine as possible). It's an entire cast of these women, with a lot of greyness and complexity and no one really being perfectly right. The men of the show are the villains who basically embody the two stereotypical villainous men archetypes and despite the MC even getting an official relationship in the end, it's not the power of love that gives our hero 4 the victory but the power that they are them and no one is going to control them. Even the originally for fanservice GL relationships became an actual decent relationship and pretty decent representation. It's generally regarded as pretty trashy and not really worth a watch and, yeah, in many ways it is with it's inconsistencies and weird choices and pacing, but it's also weirdly not. It's a very strange show I end up going back to a lot.
Also like any YGO season after 5Ds (or just even after the first half of 5Ds because wow the second half). Especially funny example is Zexal coming straight after. Hugely successful in Japan, widely hated in the west for being too cheerful and young (dub choices didn't help) straight after the dark and gritty 5Ds. But because of it's success where it counts, all seasons after have leant more into that fun and cheerful style with dark undertones. None have proves very successful despite their massive potential (Arc V is particularly frustrating because you see flashes of brilliance beyond the point where Director Ono left for Symphogear where they'd clearly set these plot points in advance and are some of the best parts of the show and what it could have been but they didn't know how to connect them to the rest of the series). But there's all worth a watch.