Ok so I'll just go off of ben gay's post template cause he pretty much touched upon a lot of the stuff I agree with it and has it laid out really well, except for a couple of minor exceptions but these aren't very large or just my thought process.
Mega Alakazam B+ to A-: M-Alakazam is an extremely underrated threat in the metagame due to its higher power, speed, and versatility. It's definitely from an offensive stand-point better than the bulk of the B+ ranked Pokemon and as such should be reflected that it's more of a contender to fall under the A rank categories.
Mega Heracross A- to B+: I made a nom for this awhile back that I don't feel like looking for right now and I'll just summarize by saying that it's wall-breaker that has a lot of issues to contend with such as it's mediocre speed stat, which leads it to be worn down in a lot of cases and as such shines against more defensive minded builds on stall and balance more so than offensive ones, which is a problem due to the caliber of these offensive threats in the meta.
Diggersby A- to B+: I think making Diggersby the win condition is much easier said than done a lot of times which is why I think this should drop. Long story short the support that necessitates Diggersby's success I believe is enough of a reason for it to go to B+
Alakazam (Regular) C- to C: Read bens post. It's actually a pretty solid utility / offensive threat in one package and I think C- is a bit low for it looking at how and where it would function in the metagame and on offensive buildds
Azelf B- to B: I'm sure
Trinitrotoluene we'll get all happy and celebrate from reading this cause he's a hyper offensive using abuser but yes I do agree Azelf should be B. I think M-Sableye + M-Diancie are a detriment but not to the point where they're the be all end all of Azelf. The playstyle it's found on is designed to implement immense pressure on teams and Azelf is a pivotal utility mon that is the key element in a teams long term goal of establishing it's end game and win condition. Under the support characteristics B- is too low for Azelf and it should sit at B and no higher due to its linearity of providing said support.
Dragalge B- to B: Read ben gays post then go find Jukains somewhere in the last several pages lol.
Serperior B- to B: I think B+ is kind of high for Serperior but B- is too low for something that can be at times a very mindless cleaner. The cons that I find that would keep it at B and not go to B+ are its poor bulk and defensive typing for OU standards with ease o being worn down due to Life Orb damage which can be picked off through certain elements of offensive and offensive threats that can be found on Balanced builds, such as Tornadus-T and Raikou.
Thundurus-T C to C+: I've only used Thundurus-T a minimal amount recently so my reasoning for moving up is pretty baseless and I rather not try to explain it and pull theory out of my ass. More than likely something I'll let ranking team or others clarify to give me a better perspective on what I may or may not be missing.
Emboar: I haven't taken the time to use this so no comment on this.
Amoonguss B+ to B: I think I brought this up when talking with ranking team and ben gay pretty much took the words right out of my mouth. The idea that its a great pivoting tool to all these threats is fantastic in theory until you come to realize that the passiveness and ease of playing around its predictability can be quite basic. There's not much more I can say that hasn't already been explained by ben so I'm agreeing with this proposal.
Jirachi A- to A: I would like to see a case for this to not go to A though, and I mean a good one, I like seeing both sides of the argument for insight purposes and I'm indifferent on this proposal.
Volcarona B+ to A-: ben wanted this to A but I think the SR weakness, Talonflame, Zard-Y, along with the fact it's sort of a pick your poison with either HP Ground or Bug Buzz is a problem I see with Volcarona in A at the moment. I'm also concerned with inflation for A rank by putting every balance breaker just by virtue of breaking a common playstyle in there. Maybe I'm just reluctant when it comes to certain rankings as seen by the lack of big jumps and disagreement with certain proposals I make and see but I think putting Volcarona, like Kyurem-B, in A is sort of a stretch for me.
Feraligatr to B-: Definitely should be ranked based off of its Dragon Dance set. I'm more inclined to say B- for the sake of using Tyrantrum and other offensive threats there in C+ as a comparison and coming to the conclusion it's more viable than what sits at that rank in terms of similar roles.
Shuckle: This is fine in C, as the teams it's used on are really select but even then defines a playstyle that when built well can put in solid work.
Torn-T A- to A: One of the biggest pains for Balance and the answers to it are generally based on careful counter play more so than prior preparation from the team-building perspective. It's accuracy with Hurricane I believe is a bit of a poor argument when you take into account the constraint it puts on builds, variety in sets and movepool, and its realistic abilities to threaten the meta-game with its solid power and high speed tier.
Kyurem-B B+ to A-: I think A is sort of pushing it for Kyurem-B personally but I'm definitely agreeing that it should rise to A-. Read the last 5 pages of good arguments to get the idea.
Mega Scizor to stay A: This one on my end can be taken with a grain of salt but I do believe that Mega Scizors capabilities are somewhat exaggerated for something that's suppose to be A+ material. I personally do not find Mega Scizor more viable or more of a threat than, say, Mega Charizard Y, and I don't believe it's on par with the team-building constraint and capabilities that can be found and should be represented for something of an A+ caliber. A lot of M-Scizors positives are based a lot on not only the set, but the necessity if we're assuming Swords Dance variants, to take very common meta-game trends out of the picture. Sure you can argue that it can pick off damage on the likes of Keldeo and Magnezone through Superpower or Knock Off when they switch in, but in many cases M-Scizor is going to find itself in extremely awkward situations in front of the likes of Talonflame, the Zards, and Keldeo and these scenarios that it somehow comes out on top as some sort of big constraint in the meta-game I feel is based on a lot of theory more so than practicality, if we're simply talking about the shift from A to A+. As an offensive threat from what I've seen and played I'm not convinced that it warrants a rank of A+ at this point in time.
Mega Altaria A+ to S: This one is sort of iffy for me. From what I've seen in SPL it's definitely one of the best megas in the tier right now. I think the reason why I'm not entirely sure of its placement as of right now is because a lot of M-Altarias positives shine based on good match-ups more so than its abilities. You could say that these good match-ups it will gain warrants S rank because it's an easily implemented asset to teams with great synergy, all around great stats, and a variety of legitimate sets with variations. However it's something that I don't think is exactly on the level of Mega Metagross and Landorus who just by being on the team already gives you the immediate edge with very minimal support. This is to the point that the lack of support needed for these two threats for comparison sakes is representative of the support M-Altaria needs, which based on its set requires a noticeable amount of more support based on the variation being used. It's also the fact that the meta hasn't necessarily had time to adapt which is an indicator to myself it's perhaps a bit too soon to jump on the S bandwagon. M-Altaria I feel has the ability to be a threat to every arch-type but not to the extremity of what our current S ranks accomplish. This isn't a case for what I would vote more so of my perspective as to why it would stay A+ and not S, basically looking at it from another perspective.