Who've the villainous force users been dueling against the last several years? If Sabine was dueling ashoka every day for the last few years, she'd be much more up to speed than someone on the fringes of the galaxy going up against nobodies with blasters, no?
Maybe. There was some EU/reference book stuff during the Prequels that said the Jedi had neglected their dueling training because they have never fought another lightsaber wielder for hundreds of years. That both makes sense and doesn't make sense. It makes sense to focus on blaster defense training, but I can't see the older masters like Yoda letting dueling slip that much. It seems like it's more of a thing you can choose to focus on if you want, because you have some Jedi like Dooku, Mace Windu, Anakin, and Obi-Wan (to a lesser degree) who focused more on dueling.