Psyduck's Confusion gives you a decent Pokemon to use against Roxie
even though you should be stomping her with mag
, and there really isn't anything else with psychic moves. HM slaves are really unnecessary, aside from that Psyduck is one of the few to be able to use Surf/Strength, the two HMs needed to beat the game.
Also uh, Azurill is not special-based, but Azurill gets Waterfall, Huge Power, Superpower, Return, Double-Edge, Ice Punch, etc etc etc. What does Psyduck get? Surf. Surf. Surf. And Ice Beam and Psychic. Guess which Pokemon learns all three, still can learn an additional move for even better coverage, and has better special attack and speed than Golduck?
Psyduck just doesn't cut it in high tier.
also shadow claw sucks