7. Wolverine - Death Of Wolverine
Right off the bat, it's worth addressing that people didn't hate Wolverine in the conventional sense of just disliking the character, as it's more or less a universal consensus that he's a pretty interesting superhero.
No, the issue with Wolverine at the time is one that many iconic comic book characters face: saturation. While Wolverine was great, he was also in damn near every comic series Marvel had going on, and this began to grate on many comic readers' nerves, even for those who liked him.
And so Marvel resolved to end this in the most extreme way possible in the Death of Wolverine series, which somewhat unsurprisingly ended with Wolverine dying by beating coated in the same Adamantium that made his claws, which would cause him to suffocate.
Though the death wouldn't last long, as Wolverine would be back in under five years, it's still worth recognising that Marvel did put him 'on ice' for a while to try and save his reputation.