Yeah S-Rank is pretty large atm, 9 Pokemon. We oughtta try and not make that rank get too crowded, it's a very specialized rank imo (in my eyes, the S-Rank is for only the absolute top tier threats in UU).
I agree with all of the changes though, Froslass and Chandelure are very worthy of the S-Rank, both Top tier, the former is the best Spiker in UU while the latter has almost zero hard counters thanks to its legendary SpA and incredible coverage in its STABs and movepool. Abomasnow too, hail is awesome in UU atm and Abomasnow also poses a great threat on his own thanks to his STABs and solid offensive stats.
I'd also suggest Krookodile for B-Rank. Krookodile is a great late-game cleaner with Moxie, and can definitely sweep his fair share of teams. Ground / Dark coverage is very solid, and Dark STAB is very good in UU despite Fighting-types being prevalent, and Crunch gets good neutral coverage across UU. This makes Krookodile an excellent late game cleaner with a Choice Scarf, and is very destructive. While he may seem outclassed by Heracross, I would say the two of them are not even remotely comparable; I guess they both have Moxie, but the two of them play very differently. Krookodile has different STAB's, which cover a different range of threats such as Chandelure, Nidoqueen, and Qwilfish, and is also immune to T-Wave, which is a plus in Krook's sweeping prowess. Krookodile also has the advantage over Honchkrow in the sense that its STAB is much more reliable, and it does not need to rely on Sucker Punch to nail faster targets.
Krookodile is also an excellent revenge killer, with his Speed being perfect for a Choice Scarf revenge killer. Pursuit is also a great move in Krookodile's favor, and this is also what makes Krookodile great in the revenge killing department. While it faces competition from Mienshao as a revenge killer, again, Krookodile revenge kills a different set of threats. Krookodile can revenge and trap things like Azelf, Victini, Raikou, lolambipom, and Mew. Pursuit is a great thing in Krookodile's favor, and allows it to trap those things it aims to revenge kill. Krookodile also has the advantage in the sense that it doesn't have to worry about a damn miss, which is death for Mienshao, and it also doesn't mind Protect either.
Overall Krookodile is a really solid Pokemon, capable of sweeping teams like a complete boss with just hazard support, and also serving as a great revenge killer in UU that can also Pursuit trap. I think he's too good for C, and has a pretty solid place in B because of how dangerous he can really be.