I don't think tf2 is a perfect game, I think it could be improved substantially. Even if slin's idea with shotclock is swept under the rug, something else can surely be done to increase the pace of the game.
Perhaps a new game similar to slin's idea, without heavys engineers and pyros. From a spectator's standpoint these classes don't really bring any interesting strategic gameplay to TF2. I don't necessarily mean we need to change 6's, I just think we should explore different avenues. We have the power to change the game, testing things out is not a bad thing.
I still enjoy playing tf2 I just don't think the game will ever grow substantially if we don't tweak some of the rules. TF2 can do better than 5,000 viewers at ESEA lan.