I don’t know if this has been mentioned before, but Gimmighoul/Gholdengo in general.
Gimmighoul is a cool mechanic with the chests being found at the tops of towers and being able to catch roaming Pokémon, but as a Pokémon itself it’s not something you’d ever want to use. Its Special stats are decent, but only 10 speed is pitiful and the only level-up moves it has are Astonish and Tackle running off 30 base attack. Even though the roaming form is faster at 80 speed, it’s still not taking anything out with the same Attack stat and just dies faster with worse defenses (and is also unobtainable).
Gholdengo on the other hand is a badass. It’s a great special attacker with pretty solid bulk and speed, a cool evolution mechanic that’s unique albeit a bit grindy, and one of the best abilities in the game that makes it immune to status moves.
It’s so badass, in fact, that not a single mandatory trainer in the game uses it on their team and you can go through the whole game without ever seeing it. Even though it’s endgame tier, Poppy uses a completely redundant Bronzong instead (as if you’d ever want to bring a Fighting-type for her anyway) and Ryme brought a Spiritomb to her rematch. I wish Game Freak would actually showcase their new Pokémon additions.
While I understand your point and for the most part I agree with it, I do feel that in this
particular instance all of this was intentional? Including Gimmighoul not being great, Gholdengo being awesome, and the latter not being used by anyone?
I feel like in this instance, while execution is debatable, it's deliberate so as to make Gholdengo stand out that much more. Gimmighoul in terms of how you find it is pretty special in that regard, that you find it in very specific locations and it's not just an ordinary Pokemon you find. You find a Chest Gimmighoul and you can catch it, and you rack up coins by running into Gimmighoul of the Roaming Form all across Paldea, who are scattered like BOTW Koroks, basically a sort of reward for exploration in open world style, befitting of SV being an open world game.
Gimmighoul itself is not good, but that's probably part of the catch to it. You find one, and upon seeing it, it doesn't look all that impressive. And you have to gather 999 coins across all of Paldea, basically encouraging you to explore the world and put in that effort.
And then Gholdengo is the big prize you get. You gather all these coins, you have a Gimmighoul, and great, you're finally ready to evolve it! And Gholdengo is there, shimmering in gold, made of 1000 coins. It even looks like a golden trophy in a way! It's a
reward! You went through all that effort and Gholdengo is the prize you get. And not only does it look like a prize, but it's a powerhouse worthy of being a reward for all that effort you put into getting one.
The fact that no one in the game uses one just adds even more to its specialness. Because of all the effort outlined, Gholdengo is by all means a rare and elusive Pokemon: it's not just something anyone can own. You have to really go out there and put in a lot of effort and explore to
earn the right to have a Gholdengo. And when you finally do...what you have is something truly special. This Gholdengo is something
you have found, that you have earned, all for yourself. Nobody in Paldea has ever been able to gather such an awesome and elusive Pokemon. So now you have something that is very much a special and beautiful prize. You discovered it, you earned it, and it's all yours.
If any Trainers in-game used Gholdengo, that would just take away from that special feeling of having something truly rare and remarkable that one would get from raising a Gholdengo. A kid who gets a Gholdengo has bragging rights. They found this Gholdengo all for themselves, and they can absolutely kick their friends' asses with it too!
Of course, the execution leaves something to be desired arguably, and that is debatable, but in this case I would argue the intention behind the way Gimmighoul and Gholdengo are designed is very clear. In this case they are
meant to be high effort, to be high reward, and to be rare and elusive. Especially Gholdengo.