Why no one complains about "overloaded" kits in dota

Because the non-overloaded kits (and often always immobile too) have something extremely unique niche and/or things they are incredibly good at that the "everything guy" doesn't have.

Like a global Silence and losing intelligence simply for dying around this person A Spell Steal that can steal anything, even ults, A Global teleport and Global Chain Lighting.

So many people in league are just homogenized stats, damages, and ratios offering nothing truly gameplay unique. Certain people can only do damage and slow, while others can do damage, slow, and have blinks dashes and shields.

The only thing the "purists" have over the overloaded kits is like + 20 base damages, which doesn't matter if the overloaded kits have the means to do their damage and potentially more than the purist because of how easy it is to get their damage across given the tools they have. Even if balanced by "gameplay" most of these abilities just throw into a person are almost always simple easy mode point and click dashes and shields.

Sure Dota has some overlaps. Both Phantom Lancer and Terrorblade both create illusions and are hard agility carries with some form of light CC. Yet they are clearly distinguished by gameplay. Phantom Lancer's illusions are meant to confuse the enemy into guessing which one is the real phantom lancer and are completely expendable as they do negligible dps with mana burn as a utility bonus.

While Terrorblade illusions are ranged and a big source of his dps, and require some level of micro. You almost often always know which one is the real Terrorblade due to BKB telling you which one the real him is, while his illusions are meant to deal damage and are played with preservation in mind.

There is no real gameplay difference between Irelia and Fiora. Both dash, heal themselves, and do tons of damage (tm), they both also have slows that can potentially be a stun under different circumstances yet still play extremely similar to one another.

I hope the mage reworks give each mage something unique that they can own to. Something involving GAMEPLAY too, not just a "press X for shield, press Y for dash" like you have done with so many of your garbage generic bruiser designs.

One of your better examples is Brand, who's unique niche that he controls is the best spell effect applier in the game, with the potential to apply Rylai Liandry dots to an entire enemy team. While other people can straight up do more damage than him under safer circumstances and direct CC better than him, they cannot be nearly as effective as applying utility spell effects.

It's really something as simple as that, Hell, even when I play Xerath and press R forcing the entire enemy team to start running around in circles for potentially 10 seconds to dodge it - is a form of gameplay conceptual CC, no other mage has this effect, even amongst the other long range siege/poke mages.