Let me summarize the points:
a) B+ does not represent Mega Alakazams viability
b) It has good matchup against BO and Balance
c) It is more similiar to Mega Pinsir and Mega Lopunny who are in A- instead to Tangrowth and Rotom-W who are in B+
d) Psychic Spam is a good playstyle with Lele
e) Celesteela, Magearna and Ferrothorn are easy to wear down
f) Jirachi can be Z-Nature Madnessed
g) People forget how fast Mega Zam is. Unboosted, nothing is faster than Mega Zam. Scarfer-> you take advantage of that. Rain abusers -> needs ton of support. Hawlucha-> only onetime use
My answer:
a) This is not an argument for a raise if you think it does not represent B+ but I can accept this as an opener for a raise proposal
b) It has a kinda good MU against BO and Balance but you provide 0 reasons. You could have said something like you can stay unmegaed to take no Spikes and how this allows it to stay healthy throughout the game. How it can trace Regenerator, commonly used on BO and Balance etc.
Even then, being kinda good against BO and Balance does not automatically make you A-.
c) Of course Mega Zam is more similiar to Mega Pinsir and Mega Lopunny compared to Tangrowth and Rotom-W. They are all Megas and are kinda fast and strong. Tangrowth and Rotom-W are pivots. If you wanna compare a mon between two rankings, use mons who do a similiar job.
d) Where is your proof? Or do you expect every reader to instantly know "yea, must be right". For you, I do think that Psychic Spam is good but Mega Zam is not needed on that playstyle. You can just as well use Victini, Hoopa-U, Volcarona with Z-Psychic or mons who just appreciate priority being blocked.
e) Ferrothorn is not even a counter. Magearna lacks reliable recovery but there is this trend with Wish Clefable. Regardless of that, AV Magearna being worn down over the course of a game is something we already know. We also know everything about Celesteela. If you said something like "Celesteela usage went down" then this would make sense
f) Jirachi is a good answer to your definition of Psychic Spam which includes Lele+Zam. However, Mega Zam Shadow Ball hurts Jirachi really hard so you do not need extreme measures like Z-Natures Madness.
g) Scarfers can be taken advantage off but Lando-T and Greninja can revengekill with U-Turn while regaining momentum. Rain does not need heavy support, just Pelipper turn 1. Hawlucha outspeeding you is a huge thing. I would have expected a recommendation to use a Hawlucha counter like Zapdos on a Mega Zam Psychic Spam team. With Static, you can also punish U-Turners with a paralysis. But you just say Hawlucha is onetimeseed.. Also with Sticky Web you can outspeed Mega Zam. If you go all out and mention the small list of options to outspeed Mega Zam, mention all to be fair.
Conclusion: Mega Zam should not rise because the reasons provided did not convince me
NGL, you're right about some of the reasons in the nom not being very good reasons or well explained, but I do think mega zam is worthy of a rise. Parts of some of these arguments are quite promising, so I'll expand on some of them.
First of all, the lop comparison. Both of which are very fast megas that have a very good offense matchup. Lop, despite being more powerful, has a worse matchup with fatter teams, struggling to break through common balance mons like Pex that Zam has no issue with. Granted, Lop does have the Encore + PuP set to give it a better matchup here, but this set has more trouble against offense and no longer has ice punch for lando, which is a problem for it. Zam doesn't need any specialized set to threaten balance, and also (as you mentioned) can trace regenerator and also has magic guard pre-mega which help it to stay healthy. I've even successfully used trace to take abilities like natural cure and poison heal to use it as a status absorber on offensive teams in bad situations to help turn the game around (it can also stay non mega with magic guard to do the same thing a little more reliably). Also, playstyles like rain give Lop trouble as the rain sweepers outspeed Lop due to swift swim, while Zam has a very good matchup with rain due to trace taking swift swim, particularly if it has energy ball (niche but an option). This is a big + for offense, which typically struggles with rain. Zam also has more defensive utility than Lop, such as being used as a heatran check due to trace + recover, which is very important as tran has very few good offensive checks, and those it does have are easily worn down if they have to come in repeatedly. Overall, I would say Lop and Zam are similar in terms of viability, while Lop is more adaptable and a little more splashable as it generally isn't paired with a particular tapu like Zam is with lele, Zam definitely has better defensive utility.
Talking about Zam's speed, you mention rain and hawlucha as things that outspeed it and threaten it. While this is true to some extent, it only really applies if Zam is already in. If Zam traces swift swim (this is not difficult, there is almost always something you can sack V rain to get Zam in easily), it can revenge all of the rain sweepers with either psychic terrain up or a little chip in Swampert's case (also remember energy ball is an option). Hawlucha is a problem, but remember you often have a Lele beside your Zam, so you can play terrain wars to try to prevent it from getting it's unburden boost, and also Lucha is not safe to set up on you and it is a roll in your favour from full. Yeah being revenged by u-turners like scarfed lando/gren isn't nice, or easy to take advantage of, but it can be done by things that punish contact attackers like static zap or tankchomp (although rare, it works on some teams). I don't really see your point in mentioning sticky web, that's the same for literally any fast mon that isnt airborne. Webs is a niche playstyle that Zam doesn't have a great matchup with to be fair, but I don't think this was the right way to mention it's poor webs matchup. We've only considered the unboosted meta in the nom, but Zam also outspeeds some other cool things like +1 gyara (as well as some worse DDers like Dragonite), which can often be problematic for offense if they don't have the appropriate scarfer, so to be able to damage all of them sufficiently in one slot is nice. It's also worth mentioning that most Zygarde don't run enough speed to outpace Zam at +1 and Espeed at +1 doesn't ohko, so while it isn't a zyg answer, it can pick off a zyg that wasn't given enough time to set up fully. Zam is also one of the rare mons that can actually deal a chunk to both gyaras, with fblast KOing mega after rocks and psychic dealing a minimum of 55 to regular, which is often enough to finish it off as it probably took some damage setting up, and it KOs after rocks if terrain is up.
You've already mentioned why Jirachi isn't a reliable answer to this, but I disagree that mentioning it's checks are really easy to wear down isn't a relevant comment. Yes we already know this, but there's no harm in mentioning it because otherwise someone comes along and mentions how it's checked by them, causing a response that addresses it with a comment about them being worn down, so it's worth getting it out of the way in the original nom. You also mentioned that Celesteela usage dropped, which is nice for it as it doesn't really have a way around it
other than zap cannon. Also I have no idea why the original nom didn't go into how Zam has gained a lot of traction as the premiere tran switch in on offense, I know srn mentioned this later but this is a pretty big point in it's favour, considering how few there are that the first few that come to mind are
balloon tran keldeo, tankchomp and rotom-w, none of which are stellar and the latter barely fits on offense. While it has little room for other options, I had some fun using encore to screw over things like CM clef (although its not a reliable option like recover, it is very fun), and a couple of other moves like energy ball for the rain matchup and dazzling gleam to lure msab are niche picks that work on some teams (although having to drop either recover or shadow ball is really horrible).
TLDR: Mega Zam for A-
Edit: Just a short bit on what I think of the other noms:
Stakataka to B-: Disagree, this mon is really hard to fit onto teams, and while it probably is one of the better C+ mons it fits in more with the good but niche stuff like Araqua far more than it does with the B- stuff.
Gengar to B+: Agree, someone has already gone into this in enough detail but idk why blace was ever considered better than this, I'll take outpacing Kart and breaking ttar over more power any day. Blace is the better stallbreaker, but Gengar is far better against the other playstyles imo.
Pex to A+: Not too sure about this one, imo people have always over prepared for pex because no one likes breaking fat regen mons by outplaying so they just make sure all their mons beat it instead. This does make pex a bit worse, but then again it is still "meta defining" due to it, which is what the S ranks are for, which makes me want to keep it there.
