That she did. But imagine if she had joined Cin Drallig in the battle. Would not have made Skywalker's time any easier, that's for sure.
But she still ran away. Wise decision? Or folly? Could be both.
Probably a wise decision. I'm thinking she saw Cin getting eviscerated (technically impaled if you played the RotS video game) and figured, Anakin's going to kill us all!
I'm going to focus on Cin Drallig for a moment, seeing as he is an interesting example of what I'm getting at. He's the temple battlemaster, trained under Yoda, and a "master" (in the classroom, least) of all seven forms. He trains Anakin Skywalker, who goes out and fights in the Clone Wars. Skywalker hones his skills on the battlefield, fighting MagnaGuards, Count Dooku, etc. He comes back and this ensues:
At the height of the war, Drallig was alerted by the High Council of a possible assault on the Temple by the Sith in 19 BBY. As Council member Mace Windu moved to arrest the Sith Lord, Drallig worked with Masters Shaak Ti and Jurokk to coordinate Temple security. When Windu failed to kill Darth Sidious, the insidious Sith sent his apprentice, Darth Vader, to secure the Jedi Temple in the name of the Dark Lords. As the 501st Legion marched on the Temple, Drallig readied his students for the assault. As clone troopers were felled on his blade, Drallig was made a priority target for elimination and Vader began hunting for his former mentor. However before Drallig and Vader could confront each other, Drallig's former student, Knight Keto, intercepted the Sith and engaged him in a duel. As Drallig rushed into the Tower of First Knowledge he witnessed Keto fall to the Sith Lord. Briefly engaging the Sith, Drallig retreated to the Room of a Thousand Fountains where a large group of younglings were being protected by several Padawans. When Vader arrived in the greenhouse, he cut down Padawans Bene and Whie Malreaux before quickly overwhelming Drallig and hacking through his shoulder. With Drallig and the older Padawans dead, the remaining children were quickly cut down by blasterfire. The incident was recorded by Temple security camera TR4-121.
(Taken from Wikipedia)
So, the battle-hardened student returns and "quickly overwhelms" his old lightsaber instructor... at one point apparently fighting one-handed while choking another padawan. I think that's a pretty clear indicator that while Cin Drallig posed "the greatest threat" to Skywalker at the temple, this was only because everyone else was either a mediocre swordsman or still just a padawan. He was a threat only relative to the other Jedi in the temple.
If you prefer the TLDR version: Combat Experience >> Sparring Practice in the Jedi Temple
Earlier, there was mention that the 1000 years of peace allowed the Jedi to practice their swordsmanship endlessly. While this may be so, that doesn't amount to much experience when compared with the extensive battlefield experience of the earlier Jedi and Sith.
Lightsaber sparring is, of course, quite dangerous. One false move would be immediately fatal, but this would not necessarily encourage effective sparring. If anything, this would make the Jedi hesitant during their dueling sessions, and would not encourage the kind of all-out fighting that would occur on the battlefield. Would you really want to be the guy who killed another Master during a "friendly duel" because you thought he would be quicker on his guard than he actually was?
There is no real substitute for an actual fight. Sparring can teach the movements and the forms of combat, but it is only the first stepping stone. Only through actual experience can one learn the rhythms of combat, the instinct for killing that attunes one to the ebbs and flows of a duel. We see this clearly when Anakin cuts down Cin Drallig.
Of course I'm not saying that the Old Republic is completely and utterly out-classed. What I am saying is that you have grievously underestimated the dueling prowess of the great masters of the Jedi Council of the Prequels.
I'm not saying that no one from the PT Era could keep up with the OR Jedi. What I am saying is that the vast majority of the PT Jedi have little to no practical combat experience. They're like champion karate competitors suddenly thrown into a warzone, where the other guy is playing for keeps and not necessarily following a "dueling sequence" so much as he's trying his honest best to slice you open with a lightsaber.
Certain members of the PT Jedi Order rose to the challenge of the Clone Wars, namely Kenobi, Skywalker, Windu, and possibly a few others, but I think this just puts them on a level playing field with the countless combatants of the older wars against the Sith.
I would also like to address one other point regarding the Force and lightsabers.
Actually those who are strong in the Force and train heavily in lightsaber combat become extremely skilled swordsmen. The ability to use those deadly weapons at such speeds requires the heightened reflexes of a Jedi.
Lightsabers are considered difficult to wield by laymen because, while technically weightless, the arc fields containing the blade generate gyroscopic effects when the weapon is swung, making it difficult to control without practice.
Are the heightened reflexes of a Jedi tied to Force sensitivity, or to the degree of a Jedi's ability to wield the Force?
The way Obi-Wan Kenobi describes the Force to Luke is as a connected field of energy, and that by attuning himself to it, he is better able to perceive his surroundings. This was apparently how he deflected blaster bolts despite having the visor down during training.
Alternatively, do Jedi's reflexes appear faster because they have precognitive abilities? If so, then they are reacting to things before they happen. This is Qui-Gon Jinn's explanation to Anakin's mother as to how he is so talented at podracing.
Or, are some Jedi using the Force Speed ability to simply move faster than their opponent is able to react to them? It is suggested that Sidious does this when ambushing the Jedi in his offices. Any of these factors must be considered when discussing "Jedi Reflexes", and evaluating their effect on physical performance.
You also have Jedi such as Orgus Din who are considered quite weak in the Force, but are formidable duelists. I've always seen the Force as being separate from dueling abilities. This is not to say that certain Force powers (namely Force Speed, but also jumps and other physical powers) are not tremendously valuable in a duel, but just that the sensitivity required to wield a lightsaber is tied solely to whether or not one can sense the Force, rather than how strong one is at controlling or channeling the Force.
those who are strong in the Force AND train heavily in lightsaber combat become extremely skilled swordsmen
These are separate concepts. Any force sensitive who trains heavily will increase his or her skill with a lightsaber, whether they are strong or weak in the Force. Those with strong Force abilities will have certain advantages over those who are weaker, but this does not reflect their swordsmanship directly.