You know when this hit me? As I was thinking about dungeon clearing techniques I realized units like SWAT, Rangers, Delta and SEALs are not fighters, they're thieves, magic user thieves for that matter (or thief magic user, whichever way you want it). The modern day "fighter" can jump off an airplane, swim underwater, climb up and down a rope, listen through walls, speak in sign language to fellow
Why not empower all classes to have fighting abilities to a higher or lesser degree and be done with the fighter as a class? Fighter is now a skill and not a class. Something you can add to other classes to a greater or lesser extent.