This may just be me, but I rather think a good movie adaptation has to first be a good movie in it's own right ahead of being accurate to whatever it may be based on. Calling Halle Berry's character in 'Catwoman' "Selina Kyle" would not have magically made that movie not god awful just as being true to the Johnny Blaze origin story did not automatically make 'Ghost Rider' objectively better.
They couldn't have done that anyway, since Berry's Catwoman implicitly coexisted with Selina Kyle in the same reality. What a lot of people don't realize about that movie is that it was a stealth spinoff of Batman Returns, taking the origin of Michelle Pfeiffer's Catwoman -- murdered, surrounded by cats, revived with catlike persona and abilities to take revenge on her murderer -- and retconning it into a mystical legacy that had been endowed on many women over the ages, the implication being that Selina had been just one of them.
But you're right, of course -- fidelity and quality are two different things. I've just been binge-rewatching the Bill Bixby Incredible Hulk series, which is beloved by Hulk fans even though it was about as far from the source as it's possible to get. Its showrunner found the comics ridiculous and tried to change everything about them, instead doing a show that owed more to Jekyll & Hyde, The Fugitive, and Universal's Frankenstein than to anything from Marvel. Yet it was the first really smart, sophisticated TV superhero adaptation, rising above the cheesiness of contemporaries like The Amazing Spider-Man and Wonder Woman, so it's well-regarded despite being almost completely detached from the source.