Despite Primeape unfortunately leaving and never returning, I always thought that this was a fantastic episode, and definitely one of the main ones that springs to mind when I think about the original series. Primeape wasn't around for long, but it was great. It had a lot of character. I'm sure people who watched at the time will remember it fondly. Primeape's story was basically Charizard's story, condensed into 5 episodes, with Primeape leaving to "train" at the end of it, similarly to how Charizard left to "train" at the Charicific Valley. Real shame it wasn't around for longer, or that we never saw it again. I guess it made sense as it had completed its "story", similarly to Butterfree. Better writing could've easily found a way for Primeape to stay though.
I always thought Geodude's inclusion was because it came under the "Fighting-type" in the TCG (Fighting, Rock and Ground). Anyway, obviously it was great seeing Hitmonchan and Hitmonlee. Team Rocket were at their best in this episode as well, shame how things have been for them more recently.
The idea of the P1 Grand Prix is always something that resonated with me as well. I really enjoyed the idea of it and I remember at the time, I genuinely expected Ash to compete in another one in the Johto region. I'm disappointed the P1 Grand Prix hasn't been mentioned since. I thought it would've made a mint side competition for Ash to enter whilst on his journey. May have possibly led to Ash getting more Fighting-types as well, like Tyrogue, Hitmontop, etc. I guess the P1 Grand Prix is just resigned to fan fiction nowadays.
Overall, a strong episode that has lasted long in the memory for me.