>>96024125Kyle is the boss and Stan is the leader (Cartman is both a boss and a leader), that's why they make such great partners, and that's why there's so many episodes/SoT where they team up against Cartman, who is competitive with them in both respects. Kyle is very impulsive and can pursue weird things on a whim, Stan is more skeptical by default and often serves as Kyle's superego to stop him from getting too ridiculous. Like in Fun With Veal and Good Times with Weapons, when Cartman proposes to kill Butters and panicking Kyle is like "I agree with Cartman!" but then Stan calms him down, and in Crack Baby Athletic Association when he keeps coming back to Stan desperate for approval. Really though, they both turn into assholes when they're not close with each other. Just look at Stan in Butterballs and how pissed Kyle is at him. Also Kyle gets sucked into Cartman's bullshit WAY MORE ever since they haven't been as close on the show, which is no coincidence, because like I said, Kyle is a boss, not a leader, so when there's no Stan he'll often let Cartman lead him. Something similar happens in Kenny Dies, when Stan is emotionally unavailable and Kyle cries in Cartman's arms. (then beats the shit out of him when he realizes Cartman was faking). They have this weird codependent dynamic where they turn really shitty without each other. Kyle is selfish and Stan likes to do things for other people, especially Kyle. Kyle gets all stressed out and Stan stays calm. Stan can get depressed but Kyle's pretty tough, and tries to make him stop being such a bitch in Raisins. They just compliment each other in so many ways. It's the lord/knight trope (which is common in romance novels btw) that exists for a good reason.
Obviously, they might be very bad for your personal tastes, but I don't think it's fair to call them simple or uninteresting objectively.