[martok2112]

Writers and actors perhaps...

....but it's when the overzealous and "self-entitled" fans start acting like they know the characters better than the writers and actors that fandom once more rears its unattractive head, and I can only shake my head in disdain.

Star Trek Nemesis for example:
Overzealous fanboy: OMG, Picard would never act like that! Picard would never drive a vehicle like that! (fan rage, fan rage, fan rage, ad nauseam).

Same thing with Galactica.
Only the writers know what Apollo, Starbuck, and the rest of the gang are capable of, or would or would not do. Fanfic writers can write up their interpretations of established characters, based on their info of what they see on screen....but, they do not have access to character traits and write ups that might give clues as to what they might do in future stories, or in given situations, unless such write ups were made publicly available.

Limiting character traits strictly according to what's been seen previously on screen severely limits character growth. Severely limits the "OH, wow, I didn't see that coming!" factor.

Fans tend to limit creative growth. That's why they are rarely (if ever) part of the creative process. There are rare exceptions. Star Trek The Next Generation practically exploded in depth when Ron Moore's script for "The Defector" was purchased from him, and then he ended up becoming a part of the production and writing team.....and when "The Defector" was bought from him, he was just a fan.

But beyond that, fans do tend to retard growth for characters and stories because they want everything to fit within their own little fan bubbles.