I was just kidding

.
OK, fair enough.
Not to get off track but I think vocal minorities in video games sometimes have an adverse effect on development. It's like always listening to the "pro players" and ignoring the "casuals" for an FPS or RTS or Fighting game.
I actually agree with this. But I also think that some ideas we see currently are interesting because they do not point the gameplay issues, they just want the game to go further. (me, civilizationfanatic2000, Boris Gudenuf,etc.)
I don't think it's true that these forums significantly affect Civ development at all. What specific features in Civ 5 or Civ 6 came from these forums
SODs criticism, ICS criticism (although devs themselves didn't want them), Corruption criticism, etc... many complaints about how it was too hard or too easy to beat a Deity game (Civ2 : farms everywhere and snowball, Civ3 : awful mechanics of siege + corruption that was advantaging middle land spawns, Civ4 city maintenance, Civ5 global happiness, Civ6 "the end is achore to reach while we know we already won", etc.) and yet, those were majorly criticisms about existing gameplay, not brand new ideas like tabula rasa or anything.
(Side note: I think it's a good thing that the devs may not be that influenced by fan discourse. I don't think fans really know what they want, and they certainly can't conceive of how to implement ideas with the same thoroughness as a professional designer.)
Well I composed a letter back in early 2000's synthesising hundreds of notes playing Civ2, and most (even bad) ideas were took from it : strategic resources, city cultural territory, colonies, among speculation of all sorts of what could be Civ. I also remember to have suggested in those forums that trade routes would form roads, at least. So in my point of view, if the "fan" feels enough passionate by its subject, it is to say the Civ series particularly, it could be of good use to the devs for inspiration.
Obviously, most fans are just waiting for the next iteration announcement and the first screenshots to be able to speculate about what they have before their eyes, not about what could be the next iteration. I agree on this that most fans don't have enough imagination to create good ideas. But there is some exceptions like mentionned before. (civilizationfanatic2000 may be to vague in his suggestions though, but at least they are a good starter, if only people didn't try to rudely discard his suggestions...)