And I third Mienshao for B-Rank.
Mienshao may look outclassed, but it's got some real good perks going for it. Firstly, it's offensive stats. 125 Attack, 95 Special Attack, and 105 Speed is very good, and allows Mienshao to wreck shop. The first cool thing is that 95 Special Attack is pretty good, so it can run Hidden Power Ice, which is a great perk to pose a threat to Landorus-T, Landorus-I, and Gliscor, so unlike the other Fighting-types, Mienshao can keep common counters at bay. Hi Jump Kick is really deadly, and coming off of 125 Attack, it's definitely gonna hurt. 105 Speed is really good and can get at Lando-I pretty well, not to mention it also outpaces Mence, which is good. Stone Edge is good too. Of course, the big ace in the hole for Mienshao is U-turn, and when paired with Regenerator, this thing can definitely keep up offensive momentum (RIP the days when I used this in conjunction with Genesect), and shrug off residual damage, and this also makes Mienshao a good fit on hail and sand teams because it kicks ass and has good synergy with Ttar/AbomaSTRONGTH. It may be frail and have trouble dealing with Ghost-types, but those are still outshined by the positive points. After all, there's a reason it got the S-Rank in UU. Mienshao should definitely be B-Rank, for it definitely fulfills a given offensive niche, and does it damn well.
Another discussion, but where should the speedy spiker Bugs that we all know of by the names of Accelgor and Scolipede be placed on the list? Perhaps D or C? Well, they are both good at spiking so they should at least be on the list.