>>55697169We will never know, but I think it's an accidental oversight and they just rolled with it
We don"t see any wrong with butterfree because it's a solid design and it arrives early in the game (and the anime) while Venomat arrives late.
It's not that butterfree flows better with caterpie, it's that venomat's evolution doesn't make sense until you put butterfree next to it.
Theories about GF wanting kids to have a "better looking early bug" don't make sense. Most green/red pokemon sprites are monstruous-looking and they weren't planning a multimedia franchise.
+ Satoshi Tajiri is a bug-catching autist. He wouldn't have let an incorrect swap slide intentionally.