The Team Rocket plot in gen 2 was so stupid. Not only is the "big threat" just the leftovers from the last game, but they don't even succeed in their goal to contact Giovanni. Even their forced evolution wave only matters for a single non-Team Rocket related battle (which ironically could help you if you catch the Gyarados and use it to sweep TR's base).

They should have made it to Team Rocket members were using underlevelled evolved Pokémon, and in the end Giovanni came in with generation 2 evolutions of gen 1 Pokémon like Steelix, merging both of their plans together.