UAV's are likely to replace manned fighters not because they become tactically superior or expendable, but because they could potentially perform anything that would kill a pilot. The F-16's pilot seat was angled back 30 degrees in order for a pilot to handle 9 G's, but even then, only the most seasoned pilots can perform such maneuvers. It's not the ability of the pilot, but the limitations of the human body that restrict a fighter's potential performance.
The F-22 and F-35 are potentially the last manned fighters we will ever see. The next generation would likely be unmanned and can perform in ways that would otherwise kill a pilot.