There are so many shitty Pokemon, types, moves, ect, and they all need to be reworked either minimally or heavily with how shit they are
A few examples:
The vast majority of Gen 1-3 mons
Types such as Grass, Ice and Rock defensively
Bug-Type
Hail as a weather condition
Stealth Rocks
ect

If you can think of anymore things that need reworking, post ITT. Also, post any changes you'd make (buffs or nerfs)