I’ve always been curious about this. I bet the default answer is that it doesn’t really happen because TV watchers are toxic and their statements are dangerous to listen to, but I’m not so sure.

I’ve heard rumors that sometimes characters will gradually develop bigger roles in a series because audiences respond well to them. (I’m thinking of Jaleel White/Steve Urkel in Family Matters and Misha Collins/Castiel in Supernatural as examples.)

In fact, I suspect that this kind of thing happens way more often than people think about. For example, the character of Harley Quinn started off as a minor henchman in Batman: The Animated Series. If audiences had responded poorly to her, would she have been featured heavily in many episodes of BTAS, added to the comics or received multiple TV shows and film adaptation (Suicide Squad, Batman and Harley Quinn, Birds Of Prey, etc.)? To me, that is an extremely clear example of a character catapulting to wide success fueled by audience approval.