This is just a personal opinion, but I've thought about it a bit and I don't think a casual/competitive split would really work.

There are players who may be really casual and be okay with being on a fully casual team, and that's fine. There's also the players that get really competitive and be okay with being on a fully competitive team. Again, that's fine. Nothing wrong with being super casual or super competitive.

I'll use myself as an example since I don't really know who else to use. I'm a pretty casual person when it comes to competitions, contrary to what it may have seemed throughout these discussions. I don't care about winning, I just care about having fun. However, I also have a bit of a competitive streak in me. I like the thrill of competition sometimes, and so I put my best effort in and have at it and hope for the best. I get a little competitive sometimes, despite being casual, but I'm not super competitive. I wouldn't be happy on a casual team because there would be no reward for my efforts other than comments on my work, and I wouldn't be happy on a competitive team because I'm just not that competitive. There might be others like me that wouldn't be happy on just a casual team or just a competitive team, so what do we do with those of us that are like that?

I'm not against the idea as a whole because it sounds like it could work, it's just that there might be others like me who wouldn't be happy on a fully casual team or a fully competitive team, and I feel like I should mention that before I forget/before you guys seriously start planning for next year's WAR.