One thing that's kind of interesting about Gen 2 coming off of a pretty in depth Gen 1 playthrough is how it's a lot more focused on strategy and overall increasing the complexity of the game.
In Gen 1 most of your Pokemon were just stat sticks that you stuck the best available moves onto, but in Gen 2 the TM selection is a lot more focused on stuff like Snore, Sleep Talk, Sunny Day, Swagger, Attract, Hidden Power, etc
I think it ends up making it seem like Johto Pokemon are a lot weaker than Kanto, but in reality it's just that the game has different priorities with a bigger focus on synergy between different moves rather than giving you the easy way out with a single win button on every monster.

Overworld interactions have also gotten a lot more complicated, with Pokemon selection and specific events depending on time of day and sometimes even days of the week - the philosophy behind rarer Pokemon has also changed, in Gen 1 the 1% encounters in areas would usually be evolved forms of Pokemon you could already find in abundance (e.g. Muk is a 1% encounter in an area where Grimers are common), while Johto will frequently hide its more desireable and unique Pokemon behind a 1% encounter rate.

I think this increase in complexity, that may or may not have been needed, kind of explains why some people might have dismissed the game originally and created the whole genwunner identity, cause they really do feel like completely different games despite the surface-level similarities.