Typically the crowd controllers is the squishy mages that coincide with medium to light builds. But considering your sarcastic remark I can only think I’ve failed to explain some details or that you refused to extrapolate a generalized fairplay mentality and or trying to impose a hyperbolic fallacy.
But let’s consider things the way they are. You can choose to be a heavy and any weapon. Let’s choose something like a mage weapon for argument sake. Ideally if you are well armored, your slow, you can take some hits. But all that armor isn’t just cosmetic it should also be encumbersome to all of your movements for better and worse in the purpose of balancing the game and so you would also slow down in your casting or blocking but also buff your knockdown resistances and if your projectiles are a direct impact of how fast you can throw your arms forward, guess what, you can’t shoot as far either. Your weapon selection is the other factor of this discussion from light, medium and heavy weapons that have particular weapon speeds. The armor should also play into the factor of how you attack. Light armor could quicken the attacks of heavier weapons as your character isn’t loaded down with extra weight and or change the animation style of the attacks to promote more variety of attacks. This would also affect the damages though as there is less weight behind the attacks. People forget that there are many styles of attacks that are used in different ways to attack specific body parts.
I propose light armor for dex builds to focus attacks on legs, arms and heads to affect stuns and slowing mobility and while there is a lack of weight behind the attacks; the damage might be reduced. This encourages dex players to use augment effects such as bleeding or poisoning to buff the damages so as to further push the get in get out combat loop of dex builds.
where medium armor would focus on arms head and torso for basic damage they are the wild card generalists of the battlefield and can buff their characters in either direction of their build to buff their damage or their ability to survive more or heavier hits.
the heavy armor users primarily focus on slow lumbering but devastating spinning and slam attacks focusing on the torso. that innertia however should also positively affect the damage. And yes should push a reliance on other teamates to root the enemy players to aid in the succession of attacks from heavy armor players.
Of course this would be an entirely new level of in depth coding and animation scheduling for the devs but at least this is out in the open for people to comment on.
To say things in a fascicios manner like why not just give heavy armor players 100000 dmg does nothing to help anyone.
I play as a light build but even I can see the game breaking nature of a 8th gate opened rock lee running around the world punching people into paste in the same way as I don’t want to see an ultimate Super Saiyan Broly laying the smack down using a sky scraper as a baseball bat.

