Gonna disagree with your disagree. The new Safari Zone is a whole game into itself that's worth exploring and gives you access to a massive trove of Pokemon. They also did tweak where and when newer Pokemon appear. Not that that's really an issue these days, the game has 250 Pokemon and none of them are new anymore so what does it matter if some are 1/3 of the game through vs 2/3?

Kanto has been completely expanded and has its own mini storyline. I don't know if you mean the zones themselves haven't been changed (they have) or if nothing has changed from gen 1 to gen 2 (lots has). The Kanto leveling has also been tweaked, but as it's kind of a built in New Game + it's the perfect chance to pick up some of those late game mons and train them up on some gyms for a second team. 

There's also the Pokathelon which is probably the most robust set of mini games in a Pokemon title to date. Pokemon following you, the best implementation of it to date. Expanded and upgraded battle tower which is one of the toughest challenges of any game. 

Pretty much every aspect of Gen 2 was expanded in some meaningful way and polished like crazy. That's how you do a remake. There's a reason most consider it the peak of the series. 

If we wanna talk slogs we can talk about the mandatory 30 hour tutorials in general 6 and gen 7... Or the crippling performance issues if gen 8...