I always find the dynamic gets so much more twisted when the other champions decide to protect Harry. It often completely upends the default Hogwarts-versus-the-world setup from the book. Suddenly, you've got Krum, this international Quidditch star, noticing how isolated Potter is during the tournament, and maybe he sees parallels to the pressure he's under. It creates this really subtle conflict with Durmstrang's reputation for dark arts—are his actions genuine, or is he trying to lull Harry into a false sense of security for some later plot? That suspicion from characters like Moody, or even Ron before they reconcile, adds a great layer of paranoia that the original tournament lacked.
The biggest conflict I see isn't even with the other schools, but internally at Hogwarts. Cedric especially gets put in a weird spot. If he's the 'good guy' trying to protect Harry too, it erases his own competitive drive and makes him a bit of a saint, which is boring. But if he's resentful because he sees Harry as a cheat getting even more special treatment—now that's interesting. It pits the Hufflepuff sense of fair play against this perceived injustice. I read one fic where his father Amos got way more involved, publicly accusing Harry of manipulating the other champions for sympathy. That kind of external pressure splitting the Hogwarts champion unity is a goldmine for drama.
Ultimately, it forces a rewrite of the entire tournament's social mechanics. The champions aren't just competing; they're forming a fragile, cross-school alliance that the host institution is deeply suspicious of. It makes the second task, where they have to retrieve 'what they'll miss most,' wildly complicated if one of them has grown to genuinely see Harry as someone they need to protect.