Yeah I agree I feel like I'm gaining some new insight into the relative power levels of these mons in the tier, this is an interesting thought experiment for sure
A little while ago I built a Physical Offence team with a Choice Band Gyarados, and figured that Sleep Talk is a good 4th move as Gyarados can check Breloom quite effectively and actually become a status absorber from coming in to take a Spore:We had a discussion on Discord today about the best users of Sleep Talk, where do you guys stand on the matter?
As for myself, I think the best Sleep Talkers are Pokemons that can switch into sleepers to begin with, ideally Breloom as it's the Pokemon you're sure is gonna use a Sleep move, and you don't wanna die off a missprediction. Switching into Venusaur is a plus but usually if you can do Loom, you can do Venu. Jynx is a lot harder I'd say and Gengar is also more dangerous to predict because you can't really know if it has Hypno and if it's gonna lands it.
I also believe an ideal Sleep Talker has multiple moves that are good in most situations to land. For example, while Crocune is a good Sleep Talker user for itself, it's not a good sleep absorber I'd say, as vs Offense, Suicune isn't too much of a threat with a 1/3 chance of pulling an offensive move and being outsped by many Pokemons.
The ones I've tested the most and liked were Heracross and Zapdos. Heracross has a good typing vs Loom/Venu/Blissey, gets a Guts boost, and cannot pick FP off Sleep Talk, which means you always pick one of Megahorn/Rock Slide, which kinda encapsulates everything (and Guts Megahorn hits hard most resists anyway). Zapdos also comes into Breloom/Venusaur pretty safely and can get three consistent rolls between Tbolt/HP/Roar while still pulling its weight consistently with these three moves alone.
Two Pokemons I've entertained to be good with Sleep Talkers but haven't tried yet are Moltres and Salamence. I've tried Metagross, which works quite well honestly but you'll have games where you Sleep Talk Boom and the opponent's sleepers hasn't been picked off so you're back to square 1.