Feel like sceptile in S is something to give consideration to, also would not place cryogonal so high myself but overall i think your list is much better
Sceptile is definitely something that I could see being S, since you have to run multiple checks to it and its rarely ever useless. Its versatility makes it super annoying to deal with, since each set is oppressive against certain teams (White Herb Leaf Storm dongs offense, Choice Specs / LO dongs a lot of balance that don't run very reliable Leaf Storm switch-ins, SD / Mixed Acrobatics can cheese a lot of those dedicated Leaf Storm switch-ins). However, I do think that its just a ~tad below everything else in S, since I don't find it nearly as oppressive as the other S-mons in general (Moltres forces you to run like 1 of 3 Pokemon to have a check to it, Durant is super splashable with Scarf but it can also do some tricky things like Baton Pass out of its counters into brokenmons or just apply a ton of pressure with CB, Alomomola invalidates a lot of the tier, Drudd trades itself for another Pokemon consistently most games and soft checks a lot of the tier). Many soft Sceptile checks are Pokemon that are generally quite good or fit naturally onto builds. For example, Drudd is an ~ok check, especially with CB Pursuit, as are Scarf Durant / Moltres, and balance cores featuring Alo / Rose or anything with Amoonguss find Sceptile pretty manageable. Absurdly strong mon, but in my list I reserved S for mons that were kinda busted imo, and Sceptile is just not as hilariously busted as the mons above it.
As for Cryogonal, that placement does seem a bit high, but honestly I've thought the mon has been kinda underrated after mr Afro Smash showed me the light back in SPL 5. Offensive LO / Icicle Plate is the most reliable spinner in the tier (Kabutops is a good Pokemon, but I find that as a spinner its actually not that great against a lot of offensive spike builds since it's relatively slow and it has issues with bulkier Rotom-N sets and bulkier Golurk sets if it lacks Waterfall) since it's fast, 1v1s Rotom-N and has recovery. It's also great at checking Sigilyph and applies a lot of pressure to builds with Kabu / Qwil as their water with slow Ice weak Pokemon (Drudd, Tang, Torterra, non Scarf Rotom-C, for example). It is a bit hard to fit onto teams sometimes since it's SR weak and lacks useful resistances and does struggle with Yache Golurk / Spiritomb (you can run Reflect to circumvent this a bit), but its matchup against offensive Spikes is definitely noteworthy, given how strong that archetype is. That being said, I could be overrating it a bit, so let me know if you guys still think otherwise!
Don't know that I would move Kabutops down that far, it's definitely a grade above Aero at the very least. Would also put Slowking either at the top of A or bottom of A+. Entei feels a bit low too, it's nowhere as good as it used to be but placing it that low, especially that low below Emboar, just feels wrong imo. I think Steelix is at least a grade better than Golurk, but I never liked lurk myself so meh. Esca also still should be an A- mon, it's better than anything else in B+ rank at least.
Kabutops is another borderline Pokemon, I kinda wanted to put it in A+ since it's a great Pokemon that fits onto a lot of teams, but at the same time it has felt a bit underwhelming on builds when I've used it. It just gets pressured a bit too hard by the stuff it wants to deal with, imo. Moltres does a ton with Hurricane, and Kabutops is often forced into Ajetting it, letting stuff like Sceptile come in for free, and being so slow, frail, and vulnerable to Spikes makes it hard to actually spin with it against offensive Spikes builds. It also kinda has some 4mss in that it wants both SD and Waterfall and needs Stone Edge / Ajet / Spin. I wouldn't really be opposed to putting it in A+, but I don't think its nearly as consistent at what it does as the other stuff in A+.
I think Slowking being in the middle of A is very fair for the mon. Defensive is still fantastic at checking stuff like Sigilyph / Fighters / Entei / Jynx, and offensive sets can be pretty scary. The meta at the moment is just not very favorable to it though, since stuff like Durant / Druddigon / Sceptile / Rotom-C threaten it so much and letting those mons get free attacks off is not fun. Still a good mon imo, but you do have to be a little careful when using it, unlike the stuff above it which generally just fit onto teams pretty easily.
Honestly I was very tempted to put Entei in B for a while, since physical attacking sets are hot garbage against so many common builds (what does CB Entei do vs Mola / Qwilfish teams other than give free Wishes to things / let Qwilfish get a billion layers, and so much stuff like Druddigon / Aerodactyl / Kabutops / Rhydon / Seismitoad check it naturally and fit onto teams so nicely, etc). However, I think A- is appropriate at the moment since SubCM Entei is actually quite decent at matchuping Alomomola builds as long as you pair it with a Tspikes absorber, and you still have to have a solid Flare Blitz switch-in or CB Flare Blitz will take lives. Also, CB Espeed is still as good as ever. It does make me feel sad putting it so low, but I just don't think the mon is as meta defining as it was before, unfortunately :(.
Steelix and Golurk tend to fit on different builds, but they're both really reliable Stealth Rockers that are fantastic at what they do so I think putting them at about the same spot is fair. Steelix is the best defensive Steel in the tier, and it's a necessary glue for a lot of balance / defensive teams as a result of that. It can definitely fit on offensive teams, since Custap Steelix is also great at getting SR up while still maintaining offensive pressure / tempo with Explosion, but generally its a bit more limited to slower builds. However, Golurk's ability to reliably set up SR, spinblock, be a Vswitch immune and provide some offensive pressure is amazing for Spikes focused builds. Additionally, something I think that's really cool about the mon is that it's just so insanely flexible. For example, it can run like, ~5 different type resist berries to check certain threats more effectively / lure things, which is incredibly cool. Yache lets you come in Cryogonal Ice Beams safely on a mispredict, Passho makes switching into Waterfall Kabutops safer, Rindo lets you come into Rotom-C and maybe catch a Sceptile / Sawsbuck with Ice Punch, Kasib works for Rotom-N, and even Colbur is usable if you wanna like, EQ a Drapion or something (ok this is probably slightly troll). That's not even getting into the weird things it can do with different gems, Custap berry, or random move choices. It doesn't really reliably counter things like Steelix does, but its very good at swinging the tempo of the game in your favor on offensive teams and its very easy to tailor it to whatever you need while providing a ton of neat utility.
Escavalier is just not a very good Pokemon, imo. Since Durant is so popular a lot of its checks are super common (Qwilfish, Moltres, Emboar, Magneton, Steelix) and being so slow + weak to Spikes just means that it often just Megahorns a resist and gives a free turn to your opponent the first time it comes in, then takes so much damage from residual that it just dies when it comes in again. This mon also probably has the worst speed tier in the tier, since it has to run a buttload of speed to beat Slowking safely, which eats into its already mediocre bulk with hazards taken into account. The mon is only redeemed by the fact that it's a Steel type and has a really strong Pursuit, which lets it make Sceptile really regret pressing Leaf Storm and eat up Psychics like Jynx / Mesprit / Uxie for breakfast. Even then, it's a Steel type that gets outsped and 2HKOed by CB Druddigon Outrage, which defeats the purpose of using a Steel type in the first place half the time.
Let me know if you guys have any other thoughts! Writing this post was super fun, and I always enjoy getting a chance to share my thoughts on BW RU things ^_^.