I dunno, the current approach seems quite reasonable. In the grand scheme of things the overwhelming majority of the Earth's surface is empty space where a plane crash is unlikely to cause much damage. You also have the complication that military pilots usually try to make sure their plane will crash in a "safe" area before they eject - many have died because they waited too long to eject trying to avoid a populated area. Giving the plan a mind of its own after they pull the handle would be unlikely to go over very well. I believe the scenario of a pilot ejecting from a perfectly good plane that keeps flying for more than a few seconds has only happened perhaps a dozen times in the entire history of aviation? Not really worth worrying about.