Would limiting the angle of attack to a maximum of 13 degrees by the fly by wire system help pilot gain advantage over his/her enemy during aerial one to one combat? Using such limits would reduce the speed loss during maneuvering.
Of course not. The pilot needs to be able to command the maximum turn capability of the aircraft when it is necessary, for, among other things, to defend against a missile that has been launched at him/her, to maneuver the aircraft into a weapons launch envelope, or to slow the adversary line-of-sight-rate for a high angle-off (heading crossing angle) gun attack.
And, actually, The F-16 flight control computer DOES limit AOA. But this is avoid loss of control due to exceeding Maximum Controllable AOA, not to prevent energy loss. The energy is there to ENABLE high AOA maneuvering when it is necessary by the pilot to either defend against a threat, or achieve a valid weapons employment solution. It would be foolish to stop the pilot from maneuvering hard enough to defeat an Air-to-Air missile, just so he has more energy when he dies.