This post is inspired by a conversation I had with someone on a forum. Alternate universe stories are pretty common, most commonly they are asking and then answering the question what if? For example what if Mary Jane was bitten by the spider instead of Peter Parker or what if Superman was raised by Lex Luthor. On this forum someone asked the question what if Ranma had battled Saffron going into the battle knowing what he learned during and immediately after the battle, basically another fight with Saffron.
There is many ways that could go. The first thing I thought was that Ranma would not let Saffron attain his ascension, child Saffron can not stop Ranma. That said I'm going to assume that Saffron has already attained his adult form and that the battle in question is the final battle versus Saffron. A lot of people view Saffron as the most powerful character in the manga, even going so far as to call him a god. Calling him a god doesn't bother me in the least since by many non monotheistic religious standards (including Shinto) he would qualify as a god (or Kami). To me it is very debatable that he is the most powerful, energy wise Herb, Happosai, Miss Hinako depending on whom/what she drains of power, Rouge in her Ashura form (a literal goddess/demoness in several religions) could probably match him or even beat him in raw power were they to really try to do so. Skill wise a lot of the characters beat him in that. Physical abilities other than healing and flight he is beat by a lot of the characters as well.
I am going to assume that the scenario (get Akane to the water) and local is the same and that Ranma has not had prep time. I also want to point out that in this battle Ranma knows about Saffron's attacks/abilities and Saffron is clueless about Ranma's (which is an extreme advantage for Ranma). Though Saffron still has several minor advantages in his favor in that as a being who can fly Saffron has an advantage for aerial combat. Saffron's regeneration beats Ranma's healing ability (which is still pretty impressive). Both are under a time limit Saffron in that he is burning himself out since his transformation was incomplete and Ranma because he has to get Akane to the water before her eyes close. Saffron still has more knowledge and practice with the magical staffs than Ranma does (recall Ranma didn't even know how to turn his on). Saffron has the advantage in that he knows Ranma's goal and can focus his entire concentration on Ranma whereas Ranma's concentration is split between fighting Saffron and getting Akane to the water (to the point that he tried to break off the battle and get Akane to the water) also Saffron knows where Ranma is trying to go whereas Saffron can go any where and attack from any direction.
Another thing I want to point out before getting to how I think the battle will go is that Saffron's statement about how his blast should have killed Ranma and his idea about how Akane blocked the blast is pretty meaningless. The reason I state this is because Saffron does not know of Ranma's abilities such as his ability to take physical punishment or what Ranma's heat tolerance is and he was just guessing. Saffron is not the first character to think that Ranma should not have survived their attack take Mikado very early in the manga, he too could not believe that Ranma survived his attack. It is possible that Saffron's theory is correct about Akane taking the heat (not that that theory makes any sense by real life physics but going by real life physics Saffron shouldn't exist either) but personally I don't like that theory since Ranma still took the physical impact (impacted the rock with enough force to compress it) and Akane was very small at the time and most of the heat would have just continued around her (Akane was like six inches tall the blast was several times her size she was not big enough to stop it). While I'm on the subject of that blast, it might have missed Ranma entirely had he not dropped Akane forcing him to change direction (Ranma stopped dodging/running in favor of catching Akane, hell he stopped paying attention to Saffron entirely in favor of catching her).
Okay here is how I think the battle would go. Ranma would pretty much curbstomp Saffron. The reason I say this is: In this scenario Ranma knows about Saffron's healing ability and that killing Saffron will only cause him to be reborn so Ranma is a helluva lot less likely to hold back. Which is something he did in the manga, once he decided that he was running out of options he sliced off Saffron's wings instead of going for a killing blow. This time Ranma would turn on the ice staff and just slice Saffron to pieces (in the manga Ranma did not know how to turn it on only did so accidentally) and Saffron has no way of stopping Ranma from doing that since he did not get the fire staff until later in the battle.
Big lead up, very disappointing fight. The reason the fight is so disappointing is because Ranma's advanced knowledge causes it to be a curb stomp. Were this a true second battle where both Saffron and Ranma have some idea as to the other opponents abilities; both are unarmed, or both are armed with the magic staffs from the beginning, or one armed with one of them the other unarmed; neither have a time limit or one of them under a time limit; etc. the battle would and could go very differently. Personally a second battle between them could go either way, hell that's how it was in the manga. Saffron had an upper-hand, then Ranma did, then Saffron, etc. the battle was much closer than most fan fics I have read make it appear to have been.
Were this a fight versus Herb than my opinion would be very different. Herb unlike Saffron was curb stomping Ranma for the majority of the time, it wasn't ping ponging between them. Even were you to give Ranma post battle knowledge prior to the battle against Herb it would not really matter. Even post manga knowledge (giving him further adaptations/better understanding of the Hiryu Shoten Ha and knowledge of the Senkens) without preptime and I'd still give Herb better odds of wining than I would Ranma (without preptime because given enough preptime the odds would/could change drastically).