Since you were the one who brought up X-Men...let me return to one irrefutable example of the original question, how did OMD ruin the Marvel Universe?
In Triumph and Torment, Marvel's greatest villain, tyrant and dictator Dr. Doom marched into hell and freed the soul of his mother from the clutches of Mephisto. In One More Day, Spider-Man, Marvel's greatest hero (or formerly in this case), caved into Mephisto and hot humiliated for a chump deal and became morally and spiritually compromised.
In the Marvel Universe, Doctor Doom has the moral high ground and truer spirit than Spider-Man himself.
This is mostly true, but I'd amend it to "Bad stories that aren't allowed to die damage Marvel" - Sins Past has never been referenced since, and in 10 years, the entire premise of a poll like this will seem absurd (one notes the retcon of The Gift, which is patently absurd on its face and was also part of a tease about Peter trying to locate his presumed dead daughter, is barely mentioned anymore when one brings up bad SM stories).
OMD, of course, has no chance of dying. It doesn't help that Marvel keeps pretending Mephisto and Peter have some sort of important connection (c.f. Scarlet Spider's last arc), but their only way out of it was either to Superboy punch it away or just let MJ and Pete get back together and never reference OMD again.
Blue text denotes sarcasm
If Sins' Past is discussed more than 10 years after its publication, the odds are that it won't be forgotten for another ten. A bad story that is forgotten happens soon or it doesn't happen at all.
The Clone Saga is still on the list of bad stories and the Post-Clone Saga era is considered a low point that JMS brought it out from (at least until Sins' past lost him a lot of good will).(one notes the retcon of The Gift, which is patently absurd on its face and was also part of a tease about Peter trying to locate his presumed dead daughter, is barely mentioned anymore when one brings up bad SM stories).
That's the major cognitive dissonance. Tom Brevoort kept going on about how OMD and stuff will never be mentioned again but you see nothing but Mephisto references all the damn times, side-jokes and pot-shots as in Charles Soule's Daredevil.OMD, of course, has no chance of dying. It doesn't help that Marvel keeps pretending Mephisto and Peter have some sort of important connection (c.f. Scarlet Spider's last arc), but their only way out of it was either to Superboy punch it away or just let MJ and Pete get back together and never reference OMD again.
It also ruins Spider-Man's stories and compromised him morally. I said it before in the Post-OMD marvel universe, Dr. Doom has moral high ground over Peter.
i got measles the other day reading a marvel comic. totally OMD’s fault
troo fan or death
My headphones detached today and I had to tape it back together. Damn you, Mephisto!
I don't blind date I make the direct market vibrate
You said OMD threw the entire Marvel Universe under a bus, but Sins Past didn't.
If all it takes to damage the entire Marvel Universe is a bad story, then One More Day is just one of hundreds of bad stories they've published over the decades. I still don't understand how a bad Daredevil vs Kingpin story could damage Galactus, or how One More Day could damage Rocket Raccoon. What impact has it had on the stories and characterization of Rocket? Do all Rocket Raccoon fans feel this way, that as part of the Marvel Universe, he was thrown under the bus by One More Day?