😐I think (and this isn't intended to be an insult) that you're arguing out of total ignorance of the situation. Palpatine did start his fight against Leia and company on the verge of death; his entire reason for being planetside to begin with was to procure Anakin Solo as a recepticle for his dark side essence. He wasn't exactly operating on a vast timetable. Carnor Jax and members of the Imperial Interim Ruling Council sabotaged the genetic makeup of Palpatine's clones, causing them to become unnaturally frail. Everytime Palpatine subsequently would call upon the Force or indulge in great emotion, he would bring himself physically closer to death. That is why his dark side adepts attempted to stop the Jedi first, before being cutdown. His physician and adepts both agreed that it was far too dangerous for Palpatine to assume combat duty given the fact that he would only harm himself more if he continued to use the Force.
That is a far more advanced stage of poor health than Luke can claim. And no, Poppunker, it isn't up for debate.
The Revenge of the Sith novelization specifically states that Dooku is on the verge of Force exhaustion, losing coordination and physical sight, which is why he has to use what little energy remains to divide Skywalker and Kenobi; they were becoming too much for him. When he was able to separate them, he called upon the Force "and the weight of his years dropped away," rejuvenating him completely.
What's your point? Luke was in no condition to continue the fight with any sense of morality or restraint; the book makes it very clear. If he wasn't in any danger, he would have been able to. But the line itself is completely unambiguous.
@ the others:
Luke's physical condition should have had no bearing on his performance against Lady Rhea. Numerous examples have been cited of physical inferior or frail individuals who were able to use the Force in such a manner that they transcended their weakness. I'd say Yoda's natural mobility as a creature of nine centuries was more restricted than even Skywalker's at that point, and yet he was able to imbue himself with superhuman levels of agility and speed so as to force Count Dooku -- who, unlike Rhea, is established as being one of the very most powerful and skilled duelists ever -- to retreat on a planet that enhanced the Count's own prodigious abilities. Sidious, too, was in a constant state of extremely poor health; the official site makes it clear that his body was "decaying," and that "the very source of Palpatine's strength was killing him." At best, you might be able to argue that Luke, at this point, was on par with both in physical frailty (though this isn't the case).
Do you know what the tremendous difference is between Yoda and Sidious and Luke? Aside from the fact that Yoda and Sidious were in similar physical states and performed better against opponents who actually mean something in the grand scheme of things, Luke possesses an attunement to the Force beyond either of them. Consider that Anakin's own Force reserves, though he did not master them, transcended Count Dooku's own from the get-go. Though Dooku was more skilled with the Force, he could not keep up with Skywalker simply because the boy's innate strength in the Force kept him from becoming exhausted.
Numerous statements in the book made it clear: Luke was able to temporarily reverse the damage of the atrophied muscles. Page 290 specifically states that Luke drew "on the Force, pulling it into himself to enliven atrophied muscles and restore dead synapses." He also told Ben that he was feeling better every second and not once is Luke's physical condition referenced during his duel with Lady Rhea and Vestara.
The truth to the matter is that if Luke is as powerful and as skilled as you all (DS, TJ, Poppunker, ect.) say he is, then he should have performed much better against a no-name whore and her protege.
The fight at the end is an awesome demonstration of Luke's Jedi ingenuity and deceptive cunning in combat, but it's a far cry from uber Force command and lightsaber skills.
Period.