In BW so many cool pokemon come too late. The villain is much more interesting and more of an antihero, but I got spoilt so stopped. Honestly I reduced my enjoyment by looking up pokemon on bulbapedia too much too. Doing it a little can make it more enjoyable, but it starts to feel less immersive and sentimental if overdone.
Emerald...ya know lol. Didn't finish that either, for the same reason I didn't finish Sapphire as a kid.
Yellow was amazing the first time as a kid on GBC, for giving all the starters and the interactable Pikachu, but when I played it later I wasn't such a fan of being given all the starters, because then you only have 2 places left in your party. You could put the starters in the PC, but it just feels wrong to put those legendary pokemon away, if you're trying to build the stongest team it definitely makes no sense to put away Blastoise and Charizard to get Ponyta and whoever the fuck, plus it messes with the story...oh cool, thanks for gifting me with your precious pokemon - I'll put it in the PC lol. Just made my character a psycho.
It's fine if you do change your party for different parts of the game, but I didn't do that when I was younger.
Still cool that Yellow exists though, as a unique experience.