I definitely think that Guild Ball can be a casual game. I’d consider most of my games casual, as I’ve yet to enter a tournament. We still try and play on the clock, as it helps keep things moving, and we stick to the rules, but it’s still just a bit of fun.
The problem is the nature of the game, it’s a sport, not a battle, war, adventure, or anything else.
Compare it to football. Whether you’re having a kick about in the park with a few mates, or playing in a professional team, the structure and game are pretty much the same. The length of the game might be set by the 90 minute clock, or just by the length of the lunch break you’ve started a game in. You can play until the clocks up and see who’s winning, or you can do first to a set number of goals. I don’t think anyone would argue that football can’t be a casual game would they?
Theres nothing stopping players being as creative as they want, there’s loads of alternative game styles out there, multiball, dodgeball etc, it’s only limited by how much time you want to put into planning a game. 40k players will spend days on a campaign. Designing scenarios, setting up terrain, coming up with a story. There’s nothing stopping GB players doing the same thing. The rookie leagues are just a small example of something that adds a new element.