What I liked about this episode the most is the way that the animé's version of the 'Box System' is introduced. Having not seen this episode before, it's only taken me about 8 years to go back and find out how it works!
Obviously on hindsight, there are so many holes that we can pick in this episode, like Mewtwo's engraving on the door, Dragonite being 'one of a kind', and the 'over 150' species, when the other regions blatantly have their own histories. Still, I did enjoy watching this episode though, although boo to TR!
I'll agree with the Mewtwo thing, but he might not have actually recognized Dragonite (For all he knew, that could have been a new pokemon, which is understandable since, had that been real life, he would have only seen it's eyes, It's sihoulette would not even be made out.).
And about the 150 thing, I think he actually mentioned there being MORE than 150 Pokemon
Bill: On this planet, there are more than 150 species of pokemon
Ash: OVER 150?!
That seemed to imply that, even back then, they stated that there were more species than just 150 pokemon.
In regards to Misty's behavior, well, Ash was kinda asking for it. I mean, he was being a bit of a braggart, so he was kinda deserving of it as well. Besides, Brock did the same thing as Misty (i.e. criticizing Ash's captures). Actually, I'm surprised that no one seemed to mention Brock doing that (In fact, it almost seems that no one noticed that Brock did the same thing as her in that scene).
Also, Another thing that surprised me was that they didn't ban this episode due to Columbine shootings. I mean, Team Rocket was blasting a Dragonite with Bazookas trying to kill it, and the FCC ignored that?! I mean, what was the point of banning the Safari Zone episode (which WASN'T a filler) for gun use, if they couldn't even ban this episode for gun use. It can't be because of it's age in comparison to the Safari episode, since Tentacool and Tentacruel was banned/skipped over due to buildings collapsing (since apparantly, monster wrecking city = world trade center kamikaze attack), and that episode was made 2-3 years BEFORE 9/11 happened.