With the various forms of lightsaber combat in the Star Wars universe, the form that Master Yoda employs suggests of a possible weakness to the dark side's sway. The history and practices of the Jedi Order have always been deeply fascinating. Their lore is famously rich and complex, so it may come as no surprise that they have multiple disciplines when it comes to wielding their weapon of choice, the lightsaber. As a result, a Jedi's preferred lightsaber form has the potential to reveal something about the that audiences have not yet seen. In Master Yoda's case, it may reveal a chink in his moral fortitude.
There are a total of Yoda, the Grand Master of the Jedi, uses this form is very interesting, as it reveals that he had the potential to be turned to the dark side of the Force.
Yoda's Dark Side Potential May Explain Why He Threatened Palpatine
Granted, those who employ Ataru are not as susceptible to dark side corruption compared to those who use other lightsaber forms (e.g., Form VII, a.k.a. Juyo/Vaapad, specifically requires the use of anger and other negative emotions). However, it could be argued that Yoda's favoring of this form of combat could have allowed him to at least flirt with dark side usage on more than one occasion. Such potential could be the reason as to how he was able to deflect Star Wars: Episode III - Revenge of the Sith. While it may be true that Yoda's centuries of study and training could have given him the knowledge he needed to counter Force Lightning, the fact of the matter is that he still knew how to react, thus increasing the likelihood of his weakness to the dark side.
What Would Yoda Have Been Like As A Sith Lord?
Yoda was the Grand Master of the Jedi for a reason. He has been around for centuries and was by far the wisest when it comes to the ways of the Force. Such seniority and experience would be Yoda's deadliest asset if he were ever to defect to the Sith. His vast intelligence and knowledge of both the light and dark side of the Force, combined with his aggressive fighting style, would make him a major force for the Jedi to reckon with, possibly making him and even greater threat than Palpatine himself. Perhaps he would change his combat method to Juyo, as it would allow him to continue his ferocious form, while also utilizing his anger and the dark side to boost his already masterful skills, much like his other would-be Sith counterparts.
All of this just goes to show how powerful Master Yoda really is. His ability to resist the dark side of the Force while also being adept at such an offensive fighting form shows the true strength of his willpower and dedication to both the light side and the Jedi Order. Thanks to Star Wars' intricate lore, Grand Master Yoda still continues to surprise audiences with the tiniest of details, and this instance will certainly not be the last time.