>>21125376GSC as a whole had some pretty bad design choices.
Want to evolve that Growlithe/Staryu/Oddish/Eevee you got early on? Too bad, one stone of each type only, ad you only get them at Cerulean. As in, after the Elite 4.
What's that? You want that cool demon dog you saw the Rockets using? Well shit, they only appear near Celadon. At night. With a 5% encounter chance.
Phanpy or Teddiursa? Only after the 8th gym, and they aren't even at Lv. 20. And they're rare as shit.
Wondering who is this gen's pseudo? Good news, no trainer uses it, and you can only find the first evolution of it in the very last dungeon, after you beat all the 16 gyms and the Elite 4. And he's rare as shit. And he's at Lv. 15.
Misdreavus, Snubbul, Smeargle? You can go throught the whole game without seeing any of them on the wild... unless you already know how to find them.
Then there was the awful TM choices, or how gym leaders and most of the trainers used pretty much Kanto-only pokémon.