Ok, after a bit of play, I nominate Psyduck for Low or Bottom tier. I haven't finished the game, but if there's anything I can say about it, it's that it's terrible throughout the whole of its time as a Psyduck. I've boxed it now - Psyduck has a lot of problems, namely:
-It's oddly weak; to put it into perspective, imagine a shittier panpour that doesn't learn anything good at all and doesn't evolve until around the sixth gym. It can't 2HKO most of the gym trainers in Clay's gym, let alone 3HKO anything he has.
-It's frail; even with eviolite, it WILL get 2HKOed by just about anything it faces. Even the stupidest shit will 2HKO it.
Honestly, you're better off catching a Panpour in lostlorn or something lol; it's a really inferior water type and I cannot be arsed enough to keep using it. It sits there and eats experience but does little else.
(On a side note, Dunsparce and Flareon have been going pretty ok.)
VGC Regionals: VGC11 Top 16, VGC12 12th Place