To give a specific example...
For over five years I worked on a quite successful online spinoff series from Buffy the Vampire Slayer
. We won awards, had a loyal audience, even inspired fanfic! We also had our own message board where folks commented on each episode and speculated about things, gave us feedback, etc.
During those five years, we killed off more than one character who had come to be genuinely loved. The fans were shocked. We put them through the wringer more than once.
As one of the writers, I absolutely listened to what the fans had to say. But I didn't simply give them every single thing they wanted. Rather, I gauged how the stories worked and which characters got what reaction. An early episode featured a character we made up--Faith's sister, Hope. Folks said they'd like to see her again someday. About two years later I brought Hope back, featuring her prominently in a season-long arc. Now another original character, Jeff, had started off with folks liking him well enough but then hating him for falling in love with one half of a couple the audience adored. I decided Jeff and Faith would become a couple, which became an integral part not only of that season's arc but the arc in the season after that. All because I listened to the readers.
But I didn't simply give them what they asked for.