Ok, I was in the middle of writing a post but stupid Firefox deleted it (don't ask me how, Idk lol) so I'm gonna make it short.
Scraggy: definitely not broken, can be beaten by Mienfoo (yes, I've seen Mienfoo surive +1 LO HJK!), Timburr, Cottonee, ScrafKrow, Croagunk (now that most run HJK over ZHB), etc.
Drilbur: my least fav out of the 3, still not broken though. Super fast speed makes it annoying, but Snover gets rid of SS and if you KO Hippo and still have Snover, Drilbur is so much easier to beat. Anything with relative bulk has the potential to beat Drilbur (just don't let it set up): Lileep, Mienfoo, Timburr, Koffing, Misdreavus (Idk if it survives LO Shadow Claw, probably doesn't with Evio), priority also helps. Lol maybe LO Squirtle could work. Fake Out then STAB Aqua Jet. xD
Murkrow: Not broken; I think it makes the metagame more fun. I've never used Rhyhorn before this round and I really like it. I hope Krow doesn't start using HP Grass though. Anyways, I think Krow promotes diversity, since there's so many ways you can beat it (but it does have many different sets to prepare for) so I think it's healthy for the metagame.
Idk just my quick thoughts!