Nick Fury. He is one of the axles of the MCU, and I've been putting him off because I wanted to bring my best game to the project. Well, the time has arrived. Note:I've not seen the Spiderman nor the Antman movies and I don't think he's in the Hulk movie. However, we're going to have a two-prong diversion over into Comics.
Over in comics, Fury started with the Howling Commandos, who in part have now been grafted to Captain America, and then got drawn into the whole SHIELD construct over time. Others are more Lore drenched; I've read a certain amount of runs with him in them. Now, Ultimates, which is the gritty fork of 616 changed up Fury some, to make him more--
Samuel L. Jackson. I don't have the particulars, as to who did it, who approved it, but they made two big mistakes. They didn't ask permission and it didn't occur to them that Samuel L. Jackson would find out. The man, a known and long time fan of comic books did find out. Much as I surmised, an interview confirms that MCU Fury is a direct result of him wanting to make sure he got paid and a ringside seat of the coolest show of comic books. MCU Fury has made his way back into the comics though I've not read those issues.
Now, Fury is a master spy, the Cold War is part of the character. He's not going to be a paragon of disclosure and will antagonize some characters fans feel very strongly about. How he is, or in fact is not, handled in fanworks tells us more about the 21st century and fandom than it does about the character. But the source has seeds of the problem, too.
Note, I've watched MCU in a very, unusual order. So I saw The Avengers before I watched Iron Man and Iron Man 2. I got to Agents of SHIELD very late (I've only seen through season 3), and Thor and Thor 2, I picked them up somewhere prior to Thor Ragnarok.
Captain America:The Winter Soldier and Captain Marvel are the prime vehicles for Nick Fury of what I've watched. Originally, I read CA:TWS in a way I now don't think the Russos earned. In the theater I thought Fury's conversation in the elevator with Steve was heavy handed. The scene with the cops cause car chase shock and awe for The Winter Soldier in Death Theater, I was thinking he almost missed the forest for the trees; Director of SHIELD having to expend energy on driving while black, realizes this is an ambush just in time. In hindsight, Steve's statement "If they're shooting at you, they're the bad guys" has layers I wasn't considering, given that it's said to Sam Wilson. But, this is N. Fury's essay.
Captain Marvel lets us have more facets of Fury. Some of it is he's not the director in 1995, but he's also more in a buddy picture movie on the trip to Pegasus and various other scenes, like washing dishes in Maria's kitchen with Carol. He gets to be our "red-blooded Earthman" foil to Vers. We see him doing some spycraft, from scotchtape faking the print lock, to sussing out the Skrull playing his boss and sending him to the wrong floor.
Now, there are significant moments in earlier films and in Agents of SHIELD. I've not rewatched them recently enough to really grapple with them, other than pointing out his powerbox to tempt Agent Coulson to reconstitute SHIELD, not really in keeping with what he said in CA:TWS. I'd call it a Golden Apple moment, and Coulson failed.
I've not looked at the full body of fanworks post-Captain Marvel. I've enjoyed some with Nick Fury. The fact that Captain Marvel comes so late in the pre-Infinity War/Endgame capstone means there were years of the Director Fury backstory being sparse, and yet that didn't seem to inspire fandom. There are many reasons, and yet, if one pulls back for a low-orbit view, more has been written with less meat to go on.