Writer-director Joss Whedon. (Dan Hallman/Invision/Associated Press)

I appear to have upset a number of readers yesterday by suggesting that I had mixed feelings about the news that Marvel is talking to “Fruitvale Station” and “Creed” director Ryan Coogler about directing the company’s forthcoming “Black Panther” movie. If Coogler wants to direct a “Black Panther” movie, that’s awesome; I hope it happens for him, and I will be extremely excited to see the result.

But my years covering the entertainment industry have convinced me that many of the assumptions we make about the way directing a big studio movie affects a director’s career and the artistic freedom directors get when they take those jobs are mistaken or overblown. As a result, I’ve become much more skeptical about how much up-and-coming directors actually benefit from making a Marvel, “Star Wars,” “Fast & Furious” or DC movie. And I’ve weighed the prospect of them slightly pepping up and diversifying some of my favorite franchises against the more idiosyncratic movies or TV shows they might be making in the time they spend in Franchise Land.

That may not be the calculation you’re making: it’s perfectly reasonable to think that directors can make more impact on culture by moving big franchises incrementally than they can with smaller, more personal movies. But it’s the one that went into yesterday’s post: I love seeing the world through Coogler’s eyes so much that I hate the prospect of a big corporation slapping heavy shades over his vision. And because it seemed like my pessimism about the benefits of franchise work didn’t come through clearly yesterday, I wanted to walk through a few of them:

1. Directors don’t necessarily achieve financial independence from big franchise movies: I think one of the big assumptions behind the idea that up-and-coming directors like Coogler, or established-but-cult directors like Joss Whedon, should take on a big, restrictive piece of studio business is the idea that they’ll get paid so well to do so that they’ll walk away with the ability to self-fund future projects or turn down future artistic compromises. But Whedon has said that he actually made more money from “Dr. Horrible’s Sing-A-Long-Blog,” a super-villain musical first released online that Whedon funded himself than he did for directing “The Avengers.” A big job isn’t a guarantee of the kind of payday that would make a director completely artistically independent.

2. Big franchises like Marvel and “Star Wars” are always going to require creative compromise: I would absolutely love to live in a creative moment when directors with distinct visions are given free rein to make their passion-project versions of superhero or “Star Wars” movies. A Marvel Cinematic Universe that is idiosyncratic in tone, subject matter and main characters as the “Star Wars” Expanded Universe would be a glorious, glorious thing.

But that’s not actually the creative moment we live in: All the forthcoming “Star Wars” and Marvel movies have to fit into a carefully constructed plot continuity that stretches across multiple movies, they have to be relatively consistent in tone, and they have to be constructed in ways that allow them to do well overseas. (There appears to be slightly more wiggle room in television, though both of Marvel’s Netflix series we have right now are hyperviolent noirs, which is homogeneity of a different kind than the mix of comedy and sincerity that defines the films.) Whedon may have gotten to put a fair bit of himself on screen in “The Avengers” and “Age of Ultron,” but his sensibility was also a match for the tone and template established in earlier Marvel movies (and also the ascendant nerd sensibility that’s now mainstream), and he’s talked bluntly about the not-always-harmonious processes that he had to get through to put those movies on the big screen.

Seeing your favorite director get hired to direct a big franchise movie might result in an installment of that franchise tinged by that director’s sensibility, but it’s not going to be a pure expression of that director’s talents. People like Christopher Nolan are the extreme exception, rather than the general rule. And it’s worth noting that it’s Zack Snyder, the financially-reliable if critically-reviled action director, rather than Nolan, who is going to be guiding the shape and tone of DC’s movies for some time to come now. I shudder to think what kind of Wonder Woman movie Patty Jenkins is going to be able to make under these circumstances.

3. Directors won’t necessarily get credit when big franchise movies do well: One of the big arguments for having up-and-coming young directors take on big franchise projects is that they will give them the credibility to get their original projects greenlit. But when a hot young director steps into a pre-existing fictional universe, how much of that project’s success or failure will actually accrue to them?

Stepping up from a smaller production to a massive franchise project may demonstrate that a director can handle a larger crew well, and that they can work harmoniously with studio executives and figures like John Mahaffie, the second unit director responsible for the action sequences in many of Marvel’s biggest films. That’s absolutely a valuable thing for a young director to demonstrate, and it could help make the case that they’re prepared to handle the rigors of a large original production. But it’s a narrower thing than suggesting that these directors will get credit for a franchise installment’s box office success. With a little bit of variation here and there, the box office for a “Star Wars,” Marvel or DC movie is fairly predictable. The director matters less than the property.

4. Doing a big studio movie doesn’t guarantee directors will get to do whatever they want next: One of the things that’s notable about the directors who are getting tapped to make Marvel, DC and “Star Wars” movies is that while they’re generally in the up-and-coming stages of their careers, they’re also already fairly established.

Rian Johnson, who is directing “Star Wars: Episode VIII,” already has three features to his credit: “Brick,” “The Brothers Bloom” and “Looper.” These aren’t compromise movies: they’re fairly personal pictures, and Johnson’s demonstrated that he could get a clutch of them made even after “The Brothers Bloom” was a critical and box office bust. The Russo brothers, who are helming the upcoming “Avengers” movies, got to do a bunch of low-rated but critically-loved TV. The story of how Coogler convinced Sylvester Stallone to do “Creed” is proof of his persuasive power — and the doors “Fruitvale Station,” rather than a big studio picture, opened for him.

It’s hugely to the benefit of companies like Disney and DC to convince talented young directors that making movies for them will create new opportunities. But those same companies are also unlikely to take risks on wholly unproven directors or truly radical visions; instead, they work with relatively proven commodities. It’s worth looking in a clear-eyed way about what those directors are getting in exchange for the artistic credibility they lend out to massive corporations.