SuperHippo did drop the ball on X-Overd, but it's not like it couldn't have been salvaged, unlike SenPro.

Missing stories and shaky event schedule at the start could've easily been remedied if they actually put more effort towards it. Kinda like how FKG still needs to add more character quests.

The rankings were easily ignored and were mostly bragging rights (though I've heard such-and-such about Nutaku/SuperHippo pocketing the profits of those, which X-O devs didn't like, or something).

Otherwise, the main story content and new characters were actually being added fairly regularly. There wasn't a serious problem in the stuff-to-do department, just that a lot of it was watered down, whether out of laziness or low priority to translate. But that's no reason to can the game before a year, especially compared to the other games on the list.