It wasn't an issue for me and never was. It's simple - don't mention it. I know that, unlike Reed's origins, Iron Man's origins are tied into a particular conflict, but it doesn't matter, anyway. No-ones ticking boxes on a calendar and counting down the days since Stark's origins, the Iron Man stories are simply there to be enjoyed.

••

When I was writing IRON MAN I retold his origin, specifically so I could get rid of the Vietnam references. I had Tony somewhere in Southeast Asia, but I did not say where. Nor did I make a specific reference to a war being fought there.

I'd say there are three categories:

REVEALS: Elements introduced so as to flesh out an existing mythology without contradicting anything that has come before. Alex Summers, the story of Peter Parker's parents, etc.

PASSIVE RETCONS: Retcons which serve to explain inconsistencies/errors, or play with audience expectations without directly contradicting established continuity. Spock's living parents (and human mother), the Thing's Aunt Petunia as a hot young babe, the Hulk's skin color being green in reprints of his origin, etc.

AGGRESSIVE RETCONS: Retcons which overwrite and totally contradict established history/characterization. Darth Vader as Luke's father, Gwen Stacy's children with Norman Osborn (ugh!), Magneto's "noble" motives and tragic backstory, much of ENTERPRISE, etc.

The information about Luke's father comes from Ben in STAR WARS. Ben could be lying (or parsing facts). That's out of character. But is it a retcon?

++++++++

This is a tricky one, to be sure. Of course, it's clearly a retcon. And, in terms of the film's storytelling itself, in which Ben is established as a key narrative tool (we learn about the Force, the Jedi, and Vader from him, with no reason whatsoever to believe he's an unreliable narrator), it's clearly a retcon.

In-universe, maybe it isn't so much of a retcon. Ben could have been lying (and was lying, as it turned out). But there are technically no established, objective facts that are contradicted by Father Vader's reveal. Just Ben's exposition. If we'd actually seen Vader and Father Skywalker existing as separate characters, it would be different.

+++++++++++++

Same with Gwen Stacy's affair with Norman Osborn. As out of character as my Uncle Sasha picking up a check but it does not directly contradict objective facts

+++++++++++

Yes, it does. There are timeline problems, at the very least. At no point could Gwen have run off for nine months (or less) and given birth in secret, based on everything we saw in the classic Spider-Man series. Each storyline flowed into the next, and Gwen had only gone to England to stay with relatives after her father's death for a short time. And she never showed signs of being pregnant (with TWINS) before, during, or after that trip.

And JMS' idea that the trip to France and the birth of the twins took place during the three-month gap supposedly caused by the reprint story in ASM # 116-118 doesn't fly, either. Every Spider-Man story during those years flowed directly or near-directly into the next, and the reprint story was modified to fit into then-current continuity, placing it squarely in-between ASM # 115 and # 119.

Uggghhh....I don't want to talk about it anymore! Hate...that...story.

As a general rule, I find retcons, or anything even remotely related that could even be mistaken as a retcon, a sign of poor writing and inability to work within the established parameters.

The only exception to this default presumption of mine is when there have been obvious hints in the past that some sort of reveal was coming and the reveal clearly fits in with the premonitions.

It's almost like most writers either wish they were working on another book so they change it to meet their stories, or they wish to make a name for themselves by screwing with continuity to put them in the momentary highlight.

As Dr. Doom would say... "bah!" 

Or rather, I hope he still says that.  Maybe that's been retconned too...