Your general idea would make a fine fan script or novel for "REVENGE OF THE JEDI"

What Motivates Luke to get Revenge on Vader when he delivers the killing blow with his lightsaber.

To me it would be boring if he just overpowered vader in anger and lopped off his head and arms like Anakin does to dooku.

I wonder if Lucas transposed Lukes original killing of vader to anakin murdering dooku?

I mean at least before he determined Jedi don't seek revenge. Maybe Luke is like a Ronin a masterless samurai and one who has had incomplete and wanting training. He acts with his emotions just like Anakin in the prequels except without a wooden hayden esque annoying voice.

I mean star wars could have had a very dark ending with Luke Standing over both the emperors and Vaders corpses and take their place as Emporer Skywalker the Tyrant.

He hunts down the rebellion and tortures and kills al his friends including han and leia. Finding out Leia was his sister only after he has her tortured to death as a criminal accomplice to traitors.