(N.B. This is probably something that other people have said before me, and better. But I just wanted to get it out.)
As much of a fan of Harry Potter as I am, one thing has always reeeeeally bothered me about the worldbuilding.
From a game design perspective, Quidditch is fundamentally broken. In fact, it seems to be a lot like Monopoly, in that in Wizarding culture it’s so traditional as to be sacrosanct, but the actual rules design sucks.
(Now, it’s been pointed out to me that Quidditch’s brokenness is JK Rowling’s intentional reference to the ridiculousness of cricket, which seems fair — and even if it wasn’t, one of the themes of the books is that Wizarding culture is traditional and stubborn to the point of self-destruction, so keep in mind that I’m not blaming JK Rowling, but rather the culture that she created, for the badness of the rules of Quidditch.)
Why is it bad? Because basically, the Seekers are the only ones that matter. Except in a few offhandedly mentioned corner cases, the Seeker that catches the Snitch wins the game, because otherwise your team has to be 300 points behind in which case you have no reason to want to catch the damn thing at all. The Keepers and Chasers barely matter at all, and the Beaters are pretty much only there to keep the heat off their team’s Seeker.
The thing that’s really frustrating, though, is that it’s such an easy fix. The secret to making the game fair, while keeping its essential flavor and increasing everyone’s usefulness? Make the Snitch worth zero points. It still ends the game, Seekers still exist, et cetera. But the Snitch isn’t worth anything, points-wise.
Now, with that one tiny rules change, how it would play out is this: The Chasers, Keepers, and Beaters are still trying to score as many points as they can. But for Seekers, the game is very different depending on whether your team is ahead or behind in the points. If you’re ahead, you’re trying to grab the Snitch and end the game before the other team catches up. If you’re behind, you’re running defense, distracting the other Seeker and keeping him/her from grabbing the Snitch until the rest of your team has a chance to catch up.
Suddenly, everyone’s important to the overall skill of the team, but the Seekers still control the pace of the game, it still has the same quality of “bam it’s suddenly over”, and now the game is more interesting for everyone including Seekers.