>>13227957Orange League was basically a filler arc for the gap between Gen 1 and Gen 2.
Johto is basically Kanto all over again.
Seriously, you can watch the series if you want, but in general, things are VERY formulaic up until arguable Hoenn and Sinnoh, which are also formulaic, but at least mix up the formula A LITTLE with the new evil teams and the addition of contests.
the biggest shake up in the ENTIRE SERIES is Unova, and that starts to fall flat about 30 episodes in, possible due to the fuckstorm with Rocket Vs. Plasma, though it does seem much faster paced than any other region.
I'd reccomend giving ALL the movies a watch though, even though some are much better than others.