A few changes I would like to recommend. First off:
Chatot for A rank. I've pretty much been using Chatot on nearly every team I could possibly fit it on just because of how incredible it is with the right support. Stall is a really powerful playstyle in the current meta, and NP Chatot can pretty much single handedly 6-0 stall teams with little support. Really the only thing that even wants to take on Chatot on a common stall team is Bastiodon, but with a little bit of support from a fellow teammate, Chatot has no issue leveling defensive teams with a +2 Boomburst. Its shit defensive typing and poor bulk seems like it would keep it from ever setting up, but because of the huge prevalence of set up sweepers and defensive Pokemon in the tier, Chatot has no issue fucking them over with a well timed Encore and proceeding to set up in their face. Chatter lets it bypass Ghost-types, mainly Gourgeist and Misdreavus. Combined Chatot with Sticky Web support, and you got a Pokemon that can rip through both offensive and defensive teams. Hell, Chatot doesn't even need to set up against slightly weakened offensive teams. It's just so powerful, and threatens nearly every archetype out there. Its downsides obvious, but its positives easily outweigh the negatives IMO. True bird jesus, a potent wallbreaker AND sweeper.
Also I feel like
Poliwrath should go to S rank. It's unarguably the best defensive Pokemon in the tier, and it glues so many teams together. Not only does it check a huge portion of the PU tier, such as Sneasel, Carracosta, Barbaracle, Golem, Piloswine, Purugly, Tauros, and Marowak, but it's also an outstanding Pokemon in general. RestTalk Circle Throw with hazard support makes it a bitch to face, and I've even seen bulky offensive sets to work too, seeing as how easy it is for it to set up on many threats. While it does have exploitable weaknesses, the support it provides to many teams is undeniable. Pretty much every team would benefit from it in someway. It's an S rank defensive/support threat.
Rotom-F should be in A rank IMO. It's one of the best revenge killers in the tier with a Choice Scarf, and its offensive typing makes it a bitch to deal with. To best honest, it's pretty much a staple on most offensive teams just because of the sheer amount of Pokemon it keeps in check. The LO SubSplit set severely pressures stall, while the Choice Specs set is near impossible to switch into. It has an array of other support moves too such as Will-O-Wisp and Thunder Wave, and it's quite bulky. Its Ice-typing sucks defensively and it's weak to SR, but much like Poliwrath it can fit onto a wide variety of teams, making it a great glue Pokemon. I feel like it compares a lot more offensively with the Pokemon in A rank.