And without tailglow, Manaphy would be a slightly better Phione. What's your point? Donphan has a better movepool and a better defensive typing to go along with sturdy and leftover recovery. Donphan is a spinner and Piloswine is not. Half of the spinners in OU would likely be RU or lower without rapid spin. The only spinner that might have stayed OU is Excadrill which is why it is considered to be the best spinner in OU and why defog is a more popular alternative in the current metagame.
I may have found a new set to use on donphan. Rock polish sweeper. In the past this was considered more or less a joke, and to be honest, it's still ridiculously gimmicky. However, with weakness policy it becomes somewhat usable.
Donphan @ Weakness Policy
Ability: Sturdy
EVs: 252 Spd / 252 Atk / 4 HP
Adamant/Jolly Nature
- Flail
- Earthquake
- Knock Off/fire fang/endeavor/stone edge/ice shard
- Rock Polish
Flail is used because of the sturdy abuse of this set. At one HP, Flail is effectively 200 BP. With sturdy, Donphan is able to take any hit at full health and live. Because of this, Donphan is able to take super effective hits and survive in order to obtain a weakness policy and rock polish boost. After a rock polish a jolly max speed donphan reaches 436 speed after a rock polish. For reference, this is only 2 points of speed below base 150 speed pokemon running max speed and a beneficial nature. And outspeeds base 80 speed scarfers like chadelure. At +2, donphan is able to OHKO physically defensive rotom-w at full health 56.3% of the time and 100% of the time with rocks or adament nature! Earthquake and flail are basically mandatory for Donphan to carve a niche out for itself as a sweeper, but the third slot is a pick your poison coverage move. Donphan is likely going to be walled by something, so endeavor is the probably the best choice as a last ditch effort against pokes like skarmory, but ice shard does allow Donphan to KO weakened priority users and knock off allows Donphan to beat threats like gengar more easily. Fire fang isn't really too useful, but it can be used to kamikaze kill ferrothorn and put a large dent in skarmory. Stone edge allows donphan to hit most flying types for decent damage, but this only really helps for Mandibuzz and a few OU oddities like Staraptor and flail deals with these things just as well if you are lucky enough to be brought down to sturdy. For this set to work correctly, you really need priority and rocks off of the field. Its a really gimmicky set as its somewhat difficult to pull off, but it can be effective late game sweeper that your opponent likely won't plan for and an interesting lure to take out things like rotom w late game to setup another Pokemon to sweep. Again this is not the greatest set, but can be an interesting late game sweeper.