So I've been away for a bit but I feel like some changes are worth happening, so lets talk about them
Tyranitar stays in A Rank
I personally believe Tyranitar is fine in A Rank, and while I'm not too opposed to it being in A+ rank, I prefer A Rank for it. There are too sets that regular Tyranitar commonly runs, Choice Scarf and Smooth Rock / Focus Sash support leads for Excadrill sand offense. Obviously sand offense is one of the most powerful playstyles in the game, and was once dominating both the ladder and Smogon Tour. It's slightly been adapted to I think, and while it is still an amazing Pokemon, able to setup Stealth Rocks easily, while simultaneously bearing support to a powerful playstyle, that playstyle isn't strong and dominant enough anymore for Tyranitar to maintain it's A+ Rank. I'm by no means saying it's bad, A Rank means it is a solid choice on almost any team, but Tyranitar isn't the devastating sweeper on sand, it's the Pokemon we must keep alive so that Excadrill can sweep. Like I said, I can easily be swayed, but I believe this ranking is fine for now. I'm not including Choice Scarf Tyranitar as a potential bolster to its rank as the set is very slow for a revenge killer, and while it takes on many Pokemon well, it is incredibly to easy to setup on. You just Pursuited a Latios so Mega Charizard Y can wallbreak easier? Cool, but now my Mega Gyarados / Tyranitar can setup a DD and beat your team. I just can't compare it to the powerful threats in A+ at the moment.
Gothitelle moves down to B- Rank
Honestly, the Gothitelle phase is over. Everyone and their mothers was running Choice Scarf Gothitelle for a while with the most retarded suboptimal set you could run, but it gave it hype and then people started using the Choice Specs set. With Aegislash gone and some Mega Pokemon on the rise, Gothitelle's average at best stallbreaking role has been eclipsed by the likes of actually powerful offensive stallbreakers, such as Mega Heracross, Mega Medicham, and Mega Gardevoir. It is also very easy to play around, regardless of the fact that eliminates the switching dynamic, as double switching against it is so easy to predict. Its role in the metagame just isn't that valuable at the moment, but it can still potentially help a setup sweeper beat a Pokemon, so it should be in the same rank as Magnezone, which performs similarly.
Mega Scizor moves down to A Rank
Jukain convinced me pretty well on this one, but other accomplished players have also said this as well. Make no mistake, it is still a great bulky utility check to a lot of Pokemon, such as Azumarill, Will-o-Wisp-less Mega Gardevoir, and Bisharp, while also having a decent Swords Dance set, but it fares pretty badly against many of the top threats at the moment. Some of the ones Jukain mentioned are pretty obvious: Rotom-W, Talonflame, Keldeo, Mega Charizard X and Y, Thundurus, Landorus, regular Gyarados, and Heatran are all really common and often prevent Mega Sciaor from actually sweeping, while also being great Pokemon found on most teams. Things like Latios and Greninja are being commonly seen with Hidden Power Fire for Ferrothorn, which indirectly affects Mega Scizor too. However, I find myself paraphrasing Jukain again when I say that I cannot compare Mega Scizor to other Pokemon in the A+ Rank, Mega sweepers such as Mega Gyarados, Mega Tyranitar, and Mega Pinsir, all devastating sweepers. I cannot place Mega Scizor with them.
Terrakion moves up to A+ Rank
In the Aegislash-less metagame, Terrakion is clearly tremendously better, and is a fantastic Pokemon more than worthy of A+ Rank. It has an amazing offensive Stealth Rock set, with almost flawless coverage in its STAB moves, and also having Taunt as well. It is a great lead for offensive teams and sees a lot of usage. The offensive LO set is even more devastating and has amazing coverage and amazing power and is honestly just a great offensive Pokemon, lol. I feel like I'm rambling, but when a physical Pokemon has enough coverage just to run HP Ice for Landorus-T / Physically Defensive Gliscor, it's bound to be an offensive threat. I've been running a Substitute + Swords Dance set with a Salac Berry and it's pretty great, it absolutely cleans through slightly weakened teams while being safe from revenge kills and pretty damn fast. Terrakion is still a solid Choice Scarf user though, with the raw stats and STAB combination to revenge kill all of the best Mega sweepers (Gyarados / Tyranitar / Pinsir / Charizard X). Then of course there's the absurdly powerful CB set. I can't see why this wouldn't be in A+ Rank.
Slowbro and Amoonguss move up to A- Rank, Alomomola moves up to B+ Rank
I'm grouping these Pokemon together because they're very similar: they wall a lot of shit and never die. Seriously, that's essentially it. They're all bulky as fuck and Regenerator is such an amazing ability for a defensive Pokemon that these all deserve a raise. Slowbro is a pretty good answer to a lot of Pokemon, such as Mega Gyarados, Mega Tyranitar, Mega Charizard X, Excadrill, Talonflame, Mamoswine, and it also has a reliable recovery move in addition to Regenerator. However, two of the biggest threats at the moment (Mega Medicham and Terrakion) are also walled by it, conveniently enough, so it has even more merit in this metagame. Amoonguss is an amazing defensive Pokemon that serves as an answer to three S Rank threats (Keldeo, Azumarill, and Thundurus), also never dies, and has the immensely useful Spore. It fares pretty well against a large amount of top-tier threats, and is a pretty reliable Pokemon just to put on any team. Alomomola is something I've used and loved all through XY OU, way before WCOP and even Branflakes's RMT lol, it's a great Pokemon that was supremely underrated. It's HP is absolutely massive, it has the best typing of the three Pokemon here, and takes on a variety of popular threats (a lot are the same as Slowbro). However, its offensive presence is much smaller so it can be taken advantage of with Substitute Pokemon and the like, hence a placement one rank below the other two.
The C Rank Revamp
I agree with Jukain's proposed C Rankings (for reference: Hawlucha, Bronzong, Jirachi, Goodra, Cresselia, Slowking, Alakazam, Omastar, and Mega Houndoom). I'd talk about them but I'd just end up saying the same things that he does so I'll just quote him:
i realize this is a rather massive overhaul, but i think this should be c rank if we want to operate under the definiton of 'pokemon with a niche that has a bit of merit in the meta' (as it was described to me by trc). hawlucha, nice sweeper with aegi gone. p damn strong, damn near impossible to outspeed after unburden. sub can even avoid revenge kills! bronzong, p nice check/counter to different things (sand drill, mega gard, lati@s, kyub, mamoswine, megatar, lando [kinda], pinsir [if def spread]) and sets rocks. jirachi isn't ranked but is better than these other mons anyways. nice answer to some different things too, mainly gard and lati@s, also nice against the likes of greninja, tons of utility between wish, mexican strategies, rocks, possible hw even, etc. scarf is great, can cripple a mon with trick or use the ever-valuable healing wish, able to revenge kill different things and even more with some luck plus u-turn to keep momentum in its user's favor (btw moveset: iron head / u-turn / zen headbutt / healing wish or trick). other sets like ebelt/shuca lure have been useful in my experience as well as a rocker and lure for various threats to offense. av goodra gets a lot of hate but it's alright, excellent check to various electrics and char y and beats like every non-gard/fable special attacker 1v1 (not even 2hkoed by ninja w. no rocks bc bulk). cress walls cham and lando nice n ez, reflect so dgaf about pursuit, also handles stuff like terrak, drill, and thund because it's just that fat. plus has decent recovery at least (outside of sand). slowking has a nice niche as a slowbro that actually beats keldeo basically. av set checks/counters like every special attacker every and has good coverage/spatk to boot, + regen so it stays healthy easily. sash zam is a p alright revenge killer, plus it's fast and significantly threatening offensively (though generally inferior to megazam). mg protects it from hazards/ss damage, so its sash is practically guaranteed intact at any point in the game should you keep zam out of harm's way. omastar hits really really hard in rain, 2hkoes even water resists with specs because it's just that strong. it literally only needs its water stab and maybe uses ice beam once in a blue moon, 3x water stab + ib is a very legit moveset. lo smash actually 2hkoes chansey after a boost lol, which is p cool. only issue is it competes with kabutops for a teamslot and it's kinda slow, so scarfers 100+ range can easily revenge kill it (chomp, rak, keld). megadoom can stallbreak nicely and is fast as fuck with strong stabs so matches up decently vs offense (wisp lures the counters av azumarill and tyranitar).
C- is the Rank where we see the Pokemon that we wouldn't use unless we were being very specific about what we wanted, I think C Rank is the link where we can put these things on a team if we want without it being TOO disadvantageous if not completely built around.
The rankings are pretty close to ideal at the moment, even with the new meta shifts, which is great. After this, the C rankings shouldn't need too much ironing out, all we need to wait for is Mawile to be gone