I'd say it's the 2nd worst, since gen 2 had even worse Pokemon!
I'll also say while a lot of your criticisms are fair, I don't think the Psyduck one is. It's original Japanese name has nothing to do with psychic aspects so blame the localisers for that. Besides, if you're complaining about gen 1 typing then surely Gyarados' flying type should be the one to complain about rather than Psyduck/Golduck being pure water types. Like WTF has Gyarados got to do with flying? It should have been Water/Dragon!
Well Gen 2 got all of Gen 1's rejects that didn't make the RBY cut, so you're on to something there.
Gen 2 gets my award for "Generation with the least inspired English names." Way too many mon in GSC that GameFreak did a half ass job of coming up with names for. We went from Articuno, Zapdos and Moltres to Entei, Raikou and Suicune (I freaking hate everything about Suicune: it's name sounds like suicide, no one can pronounce it right, why does it have those stupid ribbon tails that go to its face and do absolutely nothing, why is the top of its head shaped that way for no reason, and its playstyle is super boring to play against and watching paint dry is more fun). From Mew and Mewtwo to Ho-oh and Lugia (*hock spit*). GameFreak, we don't speak Japanese.
As far as Gyarodos goes, its typing actually makes sense. It and Magikarp are based on koinobori, those kites you see in Japan designed after karp. If Dark type existed in Gen 1, it probably would have been that from the get-go. Keep in mind that back then, GF wanted to keep the Dragon type rare and special, and probably felt that making it Dragon would have been too OP (it was already damn strong at the time).