The world is rooled by dops
I'll just drop a roll down this well and move on.
Revan was a Sith Lord who was considered to have immense power, with many people speaking highly of him, suggesting this consideration to be more or less accurate. Anakin was a Jedi Knight who was considered to have immense power (Mace Windu himself even said that Anakin was "arguably the most powerful Jedi alive" in the Revenge of the Sith novel). Many spoke highly of him and he has many achievements under his belt in the Clone Wars. Both had extensive experience in leadership positions in wars (Regretfully, we don't know if Revan ever personally led troops, covert teams, and such). Anakin was considered a master in his area of lightsaber combat, along with his high strength in the Force. So was Revan, but we don't know what combat forms he used, or what sort of Force powers he favored.
Who would win? There simply isn't enough information to draw a definitive conclusion. We know much more about Anakin's power than Revan's (very few of his accomplishments have actually been shown in any canonical source), and what his strengths and weaknesses in KOTOR I can't be used to argue because they could be anything. Revan at the height of his power as Dark Lord of the Sith has never actually been shown doing much; Ultimately, we really don't have any way of measuring how powerful or skilled he is except that he was very much so (which isn't enough information).
Complicating the discussion is the factor set by the main post that the Anakin in this case is Anakin without sustaining his injuries. I think I should not here that in the novel Dark Lord: The Rise of Darth Vader, Emperor Palpatine himself notes privately that Vader's real source of weakness in the suit is more psychological than anything else (quote: "Sith power rested not in the flesh, but in the will"). That said, how much weaker Vader was made by his suit is sort of a moot point in this thread. Heading back to the thread's main premise, there is again not enough information on how powerful this hypothetical Vader would be, or in what way. And how old are we talking? Do we mean uninjured Vader shortly after Episode III, where he still can be blinded by pride, arrogance, or sheer anger? Or is it an uninjured Vader many years down the road, where that weakness has been ground down by hardened Sith training and exercises, now a more cautious man? How did he expand that power of his during this time? Did he decide that his swordsmanship was good enough and start investigating more advanced Force techniques and powers, or did he move on to study of other lightsaber forms? Or did he do both? How well did his efforts go? Did dark side corruption start to affect his physical health, like it did with Cronal or the Emperor in the Dark Empire trilogy?
Therein lies the problem, in the end. There are far too many questions like this for both combatants that cannot be answered by canonical information. We don't know enough about the hypothetical Anakin (nor can we, since by nature he is non-canonical and detailed by no published source). We can speculate on how Anakin/Vader would have developed his talents or personality traits without the injuries sustained on Mustafar, but there is not enough information to declare with any certainty how he would have changed; There is no way of knowing how powerful, skilled, or anything else he would be. As for Revan, the same problem exists, albeit with one difference; Rather than simply not even existing, Revan exists, but also has no information detailing his strengths, weaknesses, and [relevant] personality traits, just as the hypothetical Anakin does. Again, we can guess, form theories, speculate, jump around, and prophesy until the spade becomes a shovel, but there are too many holes in the information we have to say who would win. We don't know how powerful either are/would be, we don't know how skilled, we don't know what psychological strengths and weaknesses they would have, and so on.
For this reason, this thread is in reality just about "which character do you like better" more than which character would have better chances of winning in single-combat.
"There is something going on in time and space, and beyond time and space, which, whether we like it or not, spells duty." -Winston Churchill
"For of all sad words of tongue or pen, The saddest are these: 'It might have been!'" -John Whittier
"Apathy is death." -Kreia