>>41485586Dark becomes physical, and Ghost becomes special, allowing the two types to actually use their STAB moves properly. Move every Gen 2 Pokemon to somewhere in Johto so you'll actually get to use them before KANTOOOOOOO. Move a bunch of the Gen 1 Pokemon to the postgame. Buff the base stats of a lot of Pokemon that need it, like Ariados. Allow more Pokemon than just Heracross access to Megahorn, let every Poison-type learn Sludge Bomb, and allow more Fire-types access to Solar Beam than just Houndoom. Add one or two more Fighting-type moves with good distribution. Expand the Crystal move tutor outside the Goldenrod Game Corner to additionally teach every TM move from Gen 1, make him available on Mon/Wed/Fri, and make it so you can have him teach moves as many times on those days as the player wants. Once the player beats the League, have all the found TMs purchasable from the Game Corner, and the Johto Gym Leaders available for rematches at higher levels once per day; beating them awards another copy of their provided TM.
For Kanto, add places where the player can actually grind instead of having everything be upwards of 20 levels below the Gym retreads.