Yeah there are better things that could get a choice scarf. I think it's kinda lolsy to lock yourself into one move just to go around Sucker Punch's speed. Weavile is pretty much superior if you're going for a fast Dark-type; it's fast, can switch moves, gets priority Ice Shard, and hits practically everything Bisharp does except Fairies. The only other thing that Bisharp really does that Weavile can't is pressure Defog users.
Sets like mixed LO, Nasty Plot, or a stallbreaking set consisting of Knock Off, Toxic, and Taunt / Magic Coat can possibly be effective against slow stall teams. The 80 base speed is pretty shitty, but just enough that it outspeeds most relevant walls. As powerful as these sets are, they're held back by major 4mss (lack of room for Gunk Shot makes Fairy-types a pain, but you really can't fit it in on most sets) and its inability to do much against more offensive teams because it can't switchin or outspeed. These sets will probably still be used, but I doubt they'll be effective outside of complimenting another sweeper by removing stall.
The sets that sound more relevant are the varying scarf sets (physical, special, and mixed). These are the only sets, outside of a SubPunch set, that fix its most crippling weakness in speed. With increased speed, its weakness to more offensive teams is limited, while it still can wreck some stall teams with its access to Trick, The major problem I see is a lack of firepower compared to other sets since you're forced to run a +speed nature. Too lazy to pull up calcs, but I assume you'll miss out on a few important KOs the other sets would normally net.
I don't know if it's broken by just theorymoning what it can do. Going by history, there's never really been something as offensive with low speed and defense banned (inb4 wobbufett family). It reminds me a lot of pre-OU Black Kyurem where it looked good on paper but ultimately was less threatening when put into practice. I think there's way too many grey areas where we can just claim it as broken just by looking at the statistics and intangibles.
Daily reminder that speed is the only stat in Pokemon that is arguably the most simplistic yet important in terms of viability.
Pretty much anything with even the slightest possibility of running u-turn is an immediate threat that forces it out.
mfw every hoopa-u i have faced have died to my 0 atk jirachi's u-turn
I would actually consider Hoopa top tier if it were not for its Speed.
...and its lack of resistences.
...and its poor physical bulk.
...and its matchup dependency.
...and its low base power movepool.
...and its weaknesses.
...and its 4mss.
Give the new toy hype time to cool down. In a few months, it'll be about mid tier competing with Black Kyurem as a slow mixed / dedicated wallbreaker.
I think it's a lot better than Kyurem-B though. Simply because of the amount of moves Hoopa-U can have and the fact that it has huge base power on both special and physical offensive stats while Kyurem-B's special attack is just "normal" compare to its physical attack. Also, remember that Kyurem-B has much major flaw than Hoopa-U's speed, which is the lack of physical moves while having a gigantic physical base power. Hoopa-U is a powerful version of Kyurem-B with all the right moves for both of its amazing special and physical offensive powers.
I agree that it's better in some aspects, but Kyurem-B is far more bulky (to the point where some defensive mons just can't break it), faster (!!!!), and has slightly better STAB options (Dragon- and Ice-type are two of the best attacking types in the game). Just the fact it's bulky and not that slow (to the point where it can outspeed Gyarados, Dragonite, Altaria, and even Landorus-T if you max its speed out) is a major boon for offensive teams, whereas Hoopa's speed and bulk just make it deadweight sometimes versus offensive teams. I absolutely think it's a killer against stall, but that point is moot since the rarity of stall in today's offensive metagame makes this an almost worthless niche. The only Hoopa set that I think can function in this metagame while holding its own weight is Scarf, which hits less harder than LO Kyurem-B and can't wallbreak anymore.
Hitting hard is always good, but so is outspeeding threats and conforming to the way the metagame operates. I think Hoopa is great in some metagames, but not in OU's fast paced and offensive one.