Yeah, I did notice that and thought it was good. Also some were just well chosen. The actress who played Tory was believable (see just seemed to have power and like that could be easily molded through training). The guy who played Miguel did a really good job too getting better with each season.
I thought Macchio was actually less believable in Cobra Kai, than he was in the Karate Kid (and he wasn't particularly believable in those but they cast him to be a wimp with a big mouth so it made sense). I think they probably could have done a better job working around Macchio's limits in the show (kind of how they did with Pat Morita). Don't get me wrong, I loved the Karate Kid growing up and I do think that was perfect casting. I just feel like they could have played Daniel's fight choreography more intelligently at times
The bigger issue I have with Daniel as a character is how filed down he got over the course of the movies and into the show. By the third movie, he doesn't really have much spirit anymore. If you go back and watch the first and second one again, he is kind of obnoxious, and it gives him a little more strength. But he feels more like Carlton in Cobra Kai: just very stiff (maybe that served the story better though: I am criticizing it now but this is one of the few shows I've enjoyed all the way through to the finale so take with a grain of salt).