Honestly I'm sick to death of Batman and Superman fighting. The situations for it are either DKR or horribly contrived (not to mention just wanting to be DKR), with the fight itself being horribly overbooked to give Batman a prayer. Not that either would be interested in the first place.I don't buy that. If it were that simple, not a single villain would have been able to use Kryptonite against Superman in the past. Its weakening effects must have a pretty large radius for any villain to have been able to use it against him. Otherwise every fight with superman against Lex Luthor would be the same as the comic above.
Also, a fight with Superman vs Batman wouldn't be a fight to the death, no matter what the DC/WB universe says.
Henry Cavill Supes should definitely just snap Batman's neck though. After all Batman wouldn't quit what choice would he have.