Just for the sake of this thread I want to point out some of the ways kamui is broken overall.
Both eyes means twice the speed, and that speed was able to overcome Juubi Jin Madara's reactions.
Literally no way at all to defend against having your entire body or part of it warped away at long range.
Warp away incoming attacks before they even reach you.
Only one attack has ever countered the intangibility, and even that had a degree of PIS to it, because Obito could've just warped himself to the kamui dimension the second the ground opened up for paper ocean.
Intangibility allows the user to travel through obstacles and barriers, and can also be extended to people that the user is touching.
Could easily be used to telefrag. Weapons the user is holding seem to also become intangible with the user, so wait until that weapon is in the opponent's body and make it solid again. Also, grab your opponent, make them intangible with you, phase them into a wall or the ground, let go, they become solid, they die.
Any attack that can't be avoided with intangibility can be avoided by warping yourself to kamui dimension.
If you get stuck in the kamui dimension, you're completely stranded, if the user wanted to they could just wait for you to die of thirst or starvation.
Can also be used to store and fire weapons.
Can be used to teleport long distance. The locations that Obito teleported to suggest that he can simply teleport to any location he wants to, whether he's been there before or not, the only exception is Kaguya's dimensions which he had to mark.
The only space-time ninjutsu that can me synched with another.
The only space-time ninjutsu that can traverse other dimensions when those dimensions aren't a specific part of the jutsu.
Warping ability can be added to attacks and weapons, though honestly the long range warp is more useful.
Teleport your essence/soul back from the pure world.
