Does training, practice and experience actually help slayers substantially?
Buffy trains hard and is normally portrayed as a technically skilled and gifted fighter but I’m a little curious whether it actually makes a huge difference.
Take Kendra for example. When she first meets Buffy, they’re both equally matched in terms of supernatural abilities, but Buffy has only had about two years of fighting experience and training whereas Kendra has presumably received martial arts training her whole life. Nonetheless, they’re almost evenly matched when they first fight due to the misunderstanding.
Then there’s Faith, who spends considerably less time training and slaying than Buffy and likely wasn’t identified by watchers and educated in fighting as a potential just like Buffy. When they face off at the end of s3, Buffy has had over three years of experience where she’s been constantly training and slaying nearly every night, and Faith has only had about a year of experience as a slayer, during which time she’s not shown to be particularly disciplined about clocking in to patrol and training. Buffy should be a considerably better fighter, but they’re still almost evenly matched and Buffy just barely beats her.
Then there’s the episode Helpless, where we’re shown that despite her skill, without her powers Buffy is pretty solidly outmatched by even regular men who are bigger than her.
The most solid conclusion you can draw is that most slayers have a very narrow range of combat ability and any training and skill they tack on that only slightly nudges their competence.