Uh... what? A random dog is somehow better than the most realistic gender differences in the series?
I do admit that Unfezant's realistic gender differences are nice and unique for it from an aesthetic standpoint, but what hurts it so much is that it's an early route Pokemon that takes after a very overdone concept for the "Route 1" archetypes, which is the bird.
Stoutland is a dog, yes, but while that might not seem *that* interesting to many that's pretty unique for the typical "Route 1" Pokemon you get. A dog is a first for a first route Pokemon you meet! Kanto established the first route mons as being a rodent, a bird, and a few bugs, and the subsequent generations followed up on that ever since and have repeated that formula ad nauseam. But even when they did, they tried to give the Pokemon of those archetypes some unique traits that made them stand out at times (well Gen 2 didn't but eh), both in terms of design *and* in terms of battle, and in some cases made them legitimately compelling to use on a team.
Gen 5 put some unique creatures in the early game that aren't your stereotypical "rat, bird, and bug" archetype, not even having bugs in the first few routes even! You had Stoutland itself, Purrloin and Liepard who are cats (okay this is kind of overdone but for Liepard being a early route mon this is fine), monkeys, a zebra, and a mole (and an *actual* mole, not Dugtrio).
But then Pidove (and Patrat too) is there and it's more or less in the early routes simply because Game Freak has to by an unwritten rule abide by the "we need a bird in the first few routes" dogma, but outside of Unfezant's well-designed gender differences, in combat they are incredibly boring to use. Pidove in battle is basically a reskinned Pidgey and doesn't really function any differently from other birds in the battle scene, whereas stuff like Staraptor, Talonflame, and even Toucannon have unique battle traits that make them more interesting in combat and meanwhile Unfezant...has nothing interesting going on. Its movepool doesn't even match up well with its stats: it has a nice support/defensive movepool and some special moves, but its stats are more like Staraptor's whereas its movepool would better work if it was bulkier/had better Special Attack, which would've made it a much more interesting Pokemon to use in combat if that was the case.
Unfezant would be easier for me to like if it was assigned to a role other than "early route bird" that has been done time and time again, but the issue I have with it is that it's incompetent in battle and its existence amongst the Gen 5 roster combined with Watchog's is a jarring microcosm of Game Freak's innate obligation to consistently reuse the same repetitive stock designs- the "generic rodent", "generic bird", "Pikaclone", etc. and Patrat and Pidove were clearly put in Gen 5 because of that unwritten rule but they made no attempts to make them unique or stand out outside of fulfilling the generic stock concepts. And when at this point we had a ton of Normal/Flying type birds already: Pidgeot, Staraptor, Swellow, Noctowl, Farfetch'd, Dodrio, etc. several of who inherently fulfill the "early route fodder" archetype themselves, Unfezant just sticks out as a boring inclusion in Gen 5's roster.
Point being, I think Unfezant needed to be more interesting than just a generic Normal / Flying bird. If it had a more interesting typing and/or more unique and interesting stats it might've stood out as a lot more unique, but it's basically a generic bird archetype and that's all it is, which is jarringly bland in a generation of Pokemon that had a lot of interesting Pokemon with unique battle capabilities, which Unfezant doesn't have.