SAO mentioned, SnK mentioned, Naruto mentioned, need to pull an obscure one outta my ass... hmmm
Rosario + Vampire!
Now now wait wait, everybody including me knew perfectly well what they were getting themselves into here, but seriously? My god I was so disappointed. All I can say is, the manga did it right, ecchi and harem sure, but they managed to weave in a dark plot that was at least pretty interesting, and the former never got in the way of the latter. The anime was utter bollocks, both seasons of it.
Oh damn it I still can't resist giving my input on SAO and SnK, screw this I SAY WHAT I WANT!
Why did you cram 2 separate virtual worlds into one season!!!??? WHY!!??? 25 episodes set in Aincrad would have been perfect, the pacing wouldn't be all over the place, the romance wouldn't have been so forced and crammed in, characters would have been given more time to develop, and you'd basically have 10/10 material right there.
Attack on Titan... Did you run out of fuel? You were speeding and power sliding through corners like a pro for about the first 10 episodes, then somehow things changed. The plot would basically go up to rocket speed then suddenly slow to a crawl for a long time. The defense of Trost part 2 was slow, but it was still acceptable. Then came the damned "Special Titan" (won't spoil it), entire episodes would be devoted to the characters just standing there and having long flashbacks, only to make way for intense action in the last 2 minutes or so. The pacing finally recovered in the end (last few episodes), so that was good.
Now that should be a problem with the pacing, not the plot right? No. Because of this retarded pacing, a lot of things were simply handwaved. To make it short, we basically still know close to jack shit about the universe SnK is set in, and why things ended up the way it did.