Funny you should talk about not saying info we know because you did that all for your magearna to S. Listen there is a reason Zygarde didn't move and I'm willing to bet Magearna is no different. They're not bad, it's that Lando-T is so ridiculously good at everything to the point where nothing is even close to it. Lando-T is the metagame. A lot of things revolve around it and certain Pokemon just can't be used or are more useful because of its exsistence. Magearna is not at that point of domination and will never be.There are some points that I definitely agree with you, but there are some arguments that don't exactly make sense.
This is info that we already know. I think you should use what changed in the current game to make a much better argument IMO. The problem with Swampert and pelipper is that they rely on each other. If they are not in the same team, they can't exactly be used individually, can they? There are arguments on the other pages of the thread about this, and read those to know why they made it B instead of B+ or A-. If you have a better argument, I think more of the VR council will seriously hear you out.(just some advice)
The reason why many people use Smeargle is that it is one or the most reliable and and fast stick web setters in the tier. Shuckle mental herb is too slow and Galvantula has problems in matchup vs Landorus and Zygarde(ground types)
However, Magearna to S makes quite alot of sense. It is now one of the most metagame defining threats and has become even better that before. We already may know that the ban of M-Metagross red to a rise of fairies and steel types and I am sure many of us agree that it is easily the best Offensive steel type in the tier. HP fire doesn't even do much, only ground can do something to it. Zygarde is killed by a trick room magearna and and it is 2 hit KOED by Fleur cannon. Landorus-T holds it back, but it is so splashable and powerful that it hardly matters. Magearnas defenses are very good considring it is an offensive pokemon. and can take hits like a wall. because of that it is a worthy contender for S.
If you wanna talk about recent meta changes with baton pass gone Magearna took a hit. It got worse, not better so in my opinion it should not move at all. It's no where near Lando-T
Magearna should stay A+
Also just a side note, recently most people think Greninja is the closest to S in terms of ou room votes.