The South Park Character Fans Admit Got Worse Over Time
It's natural for characters on TV shows to change over time. Even on sitcoms, where the natural progression is to revert to the status quo by the episode's end, characters will still change in subtle (and sometimes unsubtle) ways. The most obvious example of this is "Flanderization," which is the process in which a character becomes defined by a single trait as time goes on. It's named after Ned Flanders, who started "The Simpsons" as Homer's perfect neighbor but eventually became a parody of the Christian religious community.
"The Simpsons" may have done it first, but as tends to be the case, "South Park" followed in its footsteps and did it next. Plenty of characters have become Flanderized over the years, to the point where it's hard to recognize some of them from how they were in the earlier seasons. Fans haven't been shy of letting their opinions known of who they believe became insufferable over time.
Fans don't care for Randy anymore
On a Reddit thread discussing "South Park" characters who got worse over time, many people agreed that it's Randy Marsh. The post that kickstarted it off stated as much: "For me [it's] easily Randy, they use him too much and he's just not that funny anymore, in my opinion Tegridy Farms was the last straw." Fans just don't seem to like how Randy forces all of the attention on him, often at the expense of the fourth-graders the show is supposed to follow.
Many people pointed to the Tegridy Farms storyline as an example of how Randy takes over the show. Redditor u/Diseman81 commented, "Randy's the obvious choice. The whole show revolves around him these days and the whole Tegridy storyline has long since run [its] course [in my opinion]." Another user felt Randy was much better served as a supporting character: "I say the show was much better when people like Randy were funny side characters but usually strong side characters are no good at being main characters."
As far as why Randy has taken center stage, it seems to be a matter of creators Trey Parker and Matt Stone thinking he's the funniest. In a 2016 interview with Vanity Fair, Parker explained, "Slowly Randy — Stan's dad — became just as big a character, if not bigger, than Stan. Now, Randy's s*** is what's funny to us." It appears that as Parker and Stone have gotten older, they've found the funny side to Randy, so don't expect any other big change-ups to this formula any time soon.