If I may chime in on a somewhat old thread, you've hit the nail on the head that the OP loses sight of the reason people play paintball in the first place -- to have fun. Not necessarily to accurately put a projectile on a target, that can be accomplished at a shooting range. If that target cannot shoot back at you, it's only so fun compared to a game of closer engagement. When the sport started there was a bit of shakeout in projectiles, and though we did end up with the largest common size due to ballistics, I submit that we haven't really needed to change from that size because those ballistics are so "right."
When I first tried airsoft, I was struck by how different it was to not be able to see your projectiles or projectiles flying at you. I didn't realize how much that feedback played into my enjoyment of the game -- and my skill at the game. The effective range of a paintball coincides with a good unaided visual range that allows you to see the entire flight of your ball and judge the results of your shot at all ranges. But once you lose that connection between your shot and your target, it's simply not the same. Indeed, that's part of the very point of paintball -- seeing your hits and confirming your eliminations. The less accurate projectile keeps engagements ranges from becoming too long for that.
Also, I would think that getting sniped out constantly from long range would potentially have a negative effect on new players to paintball. Getting whacked without ever seeing who or why leaves a feeling of helplessness, like you are not good at the game and have no idea how to get better. But if you can at least see your opponent, see him shoot the ball and see it coming to hit you, you understand what happened and what you can try to do better in the future.
If I were starting from scratch hmm ... maybe I would say, have the highest level paintball tournament competition be stock class, or some fairly limited pump class.