Efficiency, size and weight will be the features of the future I think. Loader technology will undoubtedly improve as well (though I have no idea why, since we all decided that, in the interest of cheating, 15 bps was as fast as we need to shoot), probably mostly in size and weight as well. Let's face it, no human being can pull the trigger at 30 balls per second, so even if some new technology introduced devices to us that could shoot 9 million balls per second, our fingers won't allow us to shoot that fast, even in the unlikely case that the government will. Features like a sub 1.5 pound marker w/ barrel and ASA will be the selling points of tomorrow, IMO.