and Luke finishes Sidious while the two Jedi converge and kill Plagueis
Vitiate is the weak link, he isn't helping the sith unless he knows wicked battle meditation.
__________________ "Happiness is a lie. Life is horror. The light is always dying all across the universe. The last star will flicker out someday, when it does, all that remains is shadow. And I will be its king!"'-Amahl Farouk
How does Windu lose to Plagueis? Being equivalent to TPM palpatine isn't going to help against the Jedi who defeated his more powerful incarnation. Plus, Vaapad give him another edge in sabers.
Better speed, physical attributes, likely comparable saber skill. And given Plagueis's disdain for lightsaber combat, Vaapad would likely not help Windu.
__________________ "Happiness is a lie. Life is horror. The light is always dying all across the universe. The last star will flicker out someday, when it does, all that remains is shadow. And I will be its king!"'-Amahl Farouk
Windu mastered all 7 forms and defeated ROTS Sidious (although the novel implies Palpatine feigned his defeat.). His speed equaled Sidious' and even Anakin stated they were nothing more than red and purple blurs. Even if Plagueis disdains lightsaber combat and decides to use the Force, Mace can still win.