>>57942384 (OP)Slowbro is goofy and keeps the vibe from Slowpoke, showing faith in the design and an actual willingness to expand on the line. It's no wonder they kept going back to it.
On the other hand, Golduck is the most generic deviantart fakemon out of the original 151 (to the point it has a dragon/wolf shaped head) with nothing carried over from Psyduck, plus a very lame lore that says nothing besides "swims fast" (hardly a feat compared to most fish mons that are actual jets in water) and "looks like kappa" (which the Lotad line does much better) . Weaker pokemon should have memorable gimmicks, Golduck has none and that makes it forgettable, which is crazy coming from the same line as freaking Psyduck, the early anime's comic relief.