>>534342764
Knuckles' themes don't make him boring. It's just plain old bad writing that makes him boring.
Knuckles' concept should make him cool. Cool enough to literally overpower Sonic and smash him into the ground. Cool enough to be the face for all the anti-wind guys that hate on Sonic and what he represents.
But Sonic Team or SEGA or whatever completely dropped the ball. He is SUPPOSED to be "the mountain to Sonic's wind" but the truth is that they completely dropped the ball on executing any of that correctly AT ALL. Just like they drop the ball with every single one of these characters at some point. But it doesn't mean their core "theme" ruins them, because it's never the core idea itself. It's always how they execute it.
One simple solution would be to have his Guardianship be over the Chaos Emeralds as well, so he has to play treasure hunter to travel the globe and hunt them down to bring 'em back to the Hidden Palace Zone, where the Master Emerald is stored away out of anyone's sight. And, since the Chaos Emeralds are CHAOS Emeralds, they cause chaos wherever they end up, so Knuckles' job as M.E. guardian is to STOP the chaos. But look who always shows up whenever chaos is in the air... Sonic. It was probably him being a mischievous little Mickey Mouse getting himself into trouble that caused all this chaos in the first place, now the Chaos Emerald's power is about to fall into the wrong hands yet again, and now Knuckles is the one who has to deal with it! All to ensure the mistakes of his ancestors don't happen all over again.
That's just my idea, it might not be the best, but it's a way to have Knuckles be the immovable mountain, bound by his duty, AND show up frequently, and be the rival to Sonic WITHOUT having to rely on Eggman tricking him for the millionth time. SEGA is just incompetent sometimes, and it's so frustrating because they are literally sitting ON A GOLD MINE OF EPIC PROPORTIONS.