Before I make this post, I spent a decent amount of hours making a resource showing tournament w/l stats and number of times certain types were used before and after medicham. I will be using that resource for some of my points and if you want it -->
https://docs.google.com/document/d/1DvtKr7eteF90od-r9GZwtM6ioPZdLQ84pGe3BNX-0KM/edit?usp=drivesdk now onto the actual post.
So medicham is the first mon to be suspected and frankly I don't necessarily agree with this suspect as of yet and in this post I will go through the reasoning medicham is seen as broken and why In my opinion I don't think deserves a ban.
Medicham restricts teambuilding
Now restricting is a buzzword in a lot of suspects but to understand why it isnt medicham we have to look into what this actually means (or at least what my headass thinks it means zzz.) So in my experience, having your teambuilding restricted means that you can't run the best mons for your team overall but instead have to waste mon slots or move slots to counter specific pokemon. To understand why this isnt medicham we gotta look into a hypothetical scenario: what if a mon like skarmory was released in medichams place instead of day 1. Types like fighting would be able to break steel easier and without the need for keldeo, things like dragonite and diggersby arent forced to run fire punch and can instead opt for another coverage move, and things like celesteela cant run the spdef variant and are rather forced to opt for the physical variant to replace skarmory. And then skarmory is finally released. Types like fighting are now forced to carry keldeo or infernape to deal with it, more fire coverage moves like fire punch on dnite and diggers and ran to help break the steel core easier, and instead of the physical variant celesteela can now run a spdef or offensive variant meaning that types like ground now have to deal with a new threat in skarmory and a new threat in offensive/spdef celesteela. People are going to complain and say that skarmory restricts our teambuilding by forcing to prepare for a threat that wasn't previously there and also having to deal with a new threat in offensive or spdef celesteela variants that weren't previously present on steel. There might even have been a skarmory/celesteela suspect. Does that mean skarmory is broken? No, rather it means that the meta is adapting to deal with a new threat. The things that break skarmory were already viable options but weren't used because skarmory wasnt released. And honestly I believe it is the same way with medicham. Obviously some types are still going to struggle with breaking medicham but some types struggle with breaking skarmory. Just like no types 100% lose to slarmory, no types 100% lose to medicham either. Obviously, types that don't have the same tech as other types will need to carry things for specific mons. If you watch a battle between a dragon team and a dark team you can see the magearna counters without magearna even being on the field. But that doesn't make magearna broken by itself.
Psychic is the go-to type in tournament/has very few bad matchups if any
Now this is where im going to be using the "resource" I talked about earlier. Before medicham, there was certain types that got brought much more than other types and certain types got a ridiculous win percentage of over 60% when used in tournament. The most notable of these is steel. Now mind you, this is a game with about 18 usable types. So for types to have a win percentage of above 60% in tournament play is pretty insane. While normal did also go over 60% it had much less games played so that skews the results. Whereas steel has the most games played and STILL managed to get the best win percentage of every type. To further emphasize my point, ill tell you about a ladder experience I had with steel. Now I am a mediocre player, decent at best, and I have no experience with steel. Yet in my first 35 games I went 34-1 and I went to top 5 in ladder in a day. I know ladder isnt a good gauge of skill, but for a mediocre player to pick up a types hes never used and preform that well on ladder doesn't tell you about the player, but rather the type hes using. After medicham certain types are still a bit better and have more success, but now more people are able to use their steel weak types and not have to worry about as much steel spam on the ladder and in tournament, and the statistics back that up. Types like grass, normal, ice, ghost and poison are already looking like they are going to pass the pre medi usage by the ratios. Obviously its a bit early to tell but its also a bit early to say medicham is dominating the tournament scene. Especially when the w/l stats say different.
Medicham is one of the greatest wallbreakers in monotype
This is actually true but your giving him slack for doing his job well. Im sorry for bringing up a different pokemon but lets for example look at celesteela. Celesteela can be a physical setup sweeper, a special setup sweeper, physical defensive leech seed, specially defensive leech seed, assault vest max special attack, assault vest max physical attack, assault vest physically defensive, ive even seen some scarf or specs variants and each of these it pulls of spectacularly. Not to mention the fact that each set has a different list of counters and checks and its almost impossible to tell which set it is from type matchup. Now you look back at medicham. MedichM isnt that. hes the best wallbreaker in the game, but thats all he is, a wallbreaker. (Or maybe a decent late game cleaner if you run bullet punch) and even though hes the best wallbreaker around right now you deal with him the same way you deal with other wallbreakers. Hes not that fast and hes pretty frail. You just need to keep offensive pressure going and keep momentum in your favor and even medicham wont stop you from winning. Its the same for a bunch of wallbreakers. The list of counters to a wallbreaker is meant to be small, thats the point. The way to beat a wallbreaker is through the massive list of checks that they all have, medicham included. So i dont see how a wallbreaker that has a small amout of counters if any, like every other wallbreaker is a reason for banning.
Medichams offensive presence
Lets face it: medicham makes it hard for archetypes like balance to function since it poses a constant threat and it forces you to play smarter and more carefully. But is this really a new concept in monotype? I dont think so. Lets look at a mon like alolan muk. A poison team with muk is able to pressure a psychic team into not clicking psychic moves simply by being on the other persons team list. They dont even have to switch muk in once without the psychic user being too scared of getting trapped with choice mons. So this allows the poison user to make more aggressive plays and in turn swing the game in his favor. All because he had a mon on his team list. There are also examples of this with magnezone vs steel, dugdrio in general, and the one im getting into now: dd landorus. Landorus has the capability of threatening both bulky types and offensive types by being able to choose a speed boost and an attack boost. If you just sent in a choiced mon and kill ANY of my mons with an attack landorus resists, landorus basically gets to set up and for some types, thats the whole game. This relates to medicham because for types like balance to win they are forced to play more carefully than they normally would and not give medicham the opportunities he wants. Obviously, this is a great thing to force on your opponent but my point is medicham isnt the only mon with that skill.
Others
For this one im going to reply to some of the things that I didn't want to put in a huge passage.
Medicham has a ton of help in psychic.
While I don't disagree with this, I believe that its less about the type and more about how much the team composition is made to help that one mon. So unless you are using like ice, you are able to make almost any mon look good by building the team around their weaknesses and strengths.
Medicham psychic is unbeatable
I disagree with this. Psychic still has weaknesses to dd lando, ss water, ghost and dark, bug, well played poison, and powerful wallbreakers like banded kyurem, landorus incarnate, specs hydreigon, and greninja, While they aren't unmanageable, they all give psychic issues.
With mega medi around there is no reason to use mega alakazam.
I also disagree with this. Different archetypes require different mons and i think that mega alakazam is much better suited for the likes of hyper offense psychic than mega medi is. Hes fast, hes strong, and he benefits from the genesis supernova on mew. Everything about his screams hyper offense. Not tobad mention the fact that trace on mega zam prevents ho psychic from losing to weather sweepers as many ho teams are prone to doing.
CONCLUSION
I think that mega medicham isn't warranted a ban, and even if he is, I think that tournament play hasn't progressed enough to give the metagame any chance to adapt to medicham and that is why it is being perceived as broken in my opinion
P.s if you want to use the "resource" I made whether your for or against medicham I encourage you to. I didn't just make it for myself.