Bingowings said:
The Jedi order possibly returns (though we see no on screen evidence) and does achieve revenge, though it may be argued it doesn't seek it.

The Jedi Knight Anakin Skywalker both returns (from being lost in the Darth Vader personna) and achieves a revenge he actively sort.

Ok, the "Jedi" part I can maybe-kinda understand (though I still think revenge is outside of their ideals), but for the Anakin part, I must ask "He's getting revenge for what reason?"

All that we ever learn in the OT is that he was once a good man who was seduced by the Dark Side and turned on the Jedi Knights - there is no mention of him ever being seduced, manipulated, or tricked into the Dark Side by the Emperor personally or that he ever felt anger/remorse/sadness over his betray of the Jedi until he saw his son being attacked by the Emperor.

Bingowings said:
And none of these deductions require even looking at the prequel trilogy (though looking at them would make the Jedi Order seem more likely to be one to seek revenge than George Lucas would protest). They certainly do not hinge on the six part saga being pre-planned as delivered.

Yet you're specifically referencing the PT as a possible explanation to Vader's actions in ROTJ as a reason for him seeking revenge:

Bingowings said:
Anakln certainly has revenge on the man who tricked him into betraying and murdering his friends on the promise of saving his wife that his new powers drove him to destroy.

The Jedi as an order were reduced from thousands to just two and you might argue that they didn't seek revenge only the restoration of galactic freedom they certainly got it anyway....

.... Anakin kills Vader and Palpatine and he was planning to kill Palpatine for decades.