We all know that such judgments are very subjective. And in particular what irritates one reader will leave another untroubled. In my case I tend to be less troubled than most by favourite heroes being written out of character...but maybe more picky than most about happenings that just don't stand up to scrutiny.
But I do think some acclaimed Marvel classics have flaws that would lead to widespread derision in almost any other form of fiction.
Take two examples: Spider-man's origin story and "This Man...This Monster" from the great Lee/Kirby Fantastic Four run.
Spoilers...IF you're one of the dozen fans that haven't read those classic yarns.
In the Spider-man origin story...there is simply no even remotely sensible rationale for the near instant invention of the web fluid. There was nothing in Peter's new power-set that gave any credible explanation for him being able to concoct that miraculous substance from common household ingredients in about 5 minutes flat.
And if it was sort of thing he could do...then it made next ten years of stories (when he was grubbing around for money, taking photos, etc) near farcical. Just invent something else and sell it! Lot better in my view to make the webs something his own body created.
In "This Man..This Monster", the scene where the real Ben confronts the fake Thing in front of rest of the Fantastic Four is feeble beyond belief. Reed...allegedly the most intelligent man on the planet...didn't think to ask Ben or the the fake Thing a single question to establish their identity?? You know something like "What was my favourite record when we roomed at Uni together?" or some such. Come on..nobody...can be that stupid, least of all Reed.
Agree/ disagree? (Either about those examples. Or the general premise that we accept writing in comics that we wouldn't accept in other media.)