>>54127069Poliwhirl and Poliwrath are gen 1 Pokémon, so Poliwhirl didn't "get" a Poliwrath evolution, he always had one.
With that said, when he got his Politoed evo in gen 2 I did think it looked odd because it was so different, however, it was well designed and part of the large cross-gen evo theme with Bellossom, Crobat, Slowking, Steelix, Blissey, Kindra, Scizor and so on, and of course the babies, that all started with gen 2.
In hinsight, I agree; It would have been better if Poliwhirl was the final evo in gen 1, and then Politoed and a better designed more distinct Poliwrath in arrived in gen 2 together, possibly having Politoed be an entirely separate single stage mon. Have a nice day, anon.