While that is true, once Priority is gone, this things wrecks shop. Flail at 1 HP is like having base 200 power, and STAB puts it at 300. This is like using STAB Self-Festruct over and over again. Since it gets STAB normal or super effectiveness over 90%+ of the metagame, we might as well abuse it. Flail would do as much as any x4 effective elemental Punch. This sets transforms MLopunny into a late-game sweeper that is impossible to stop.
The thing is, getting a mon that weak is not only dangerous because of Hazards, passive damage, and Lopunny's own HJK, but it's almost impossible to control how weak it gets given its frailty makes it hard to find attacks it'll nearly-but-not-quite faint on without Endure, and if you reveal that without taking the hit it becomes near impossible to use effectively against a decent player.
You're also locking Lopunny out of being able to use one of its STABs effectively until it gets to around 30% health, and that Dual STAB perfect coverage is one of Lopunny's claims to fame. The things your set requires to function are essentially.
- All priority gone
- Everything needs to be worn down to some degree. Lopunny is usually used as a cleaner because her power is only above average because of her high power spammable moves. Her actual stat doesn't strike fear into walls necessarily.
- Anything with passive damage, be it Rocky Helmet, Status users that can eat one hit
- Scarf Users
- Hazard control
That's more than a bit to demand for a mon that already has other A-Ranked sets, even in something like this project. Particularly, Lopunny is a mon whose big niche is single-handedly providing a good offense match up, which this set misses out on by trying to sweep. And even then, Sub-PuP is probably better for Stall Breaking since it gives Lopunny a Buffer without leaving her vulnerable to Status and such.