They need to be solid to in order to know when they're making contact with something.
The kamui shuriken are basically just projectile versions of kakashi's kamui, & when they hit something it activates.
Obito's supposed "death" gave me an idea, so I decided to browse the various death scans in naruto. It should have been obvious but now it makes sense when I look back.
Every death in naruto has something in common [correct me if I'm wrong but I just went through the significant ones that came...
Location- Sasuke VS deidara
Distance- Sasuke VS deidara
Intel- Full
Intent- Kill
Conditions- Minato gets bunta, Naruto gets gama, this is current SM naruto
Restrictions- Kurama, ma/pa
Restrictions basically mean that the person doesn't have that particular thing, it's removed from their arsenal.
So SM being restricted would take away an SM users ability to gather natural energy altogether, therefore they can't enter it.
Deva would've annihilated neji just as easily.
Deva is much stronger than all the other paths combined. Hinata was fodder to him & neji would be as well.
MS Obito decimates kakashi
Obito can cancel kakashi's kamui, thus negating his chances of sending a clone to the dimension.
Should kakashi actually manage to send a clone to the dimension, obito can then warp there & use a large scale katon to take care of the clone from a distance. Kakashi...
He can't hit minato? Then he hits the kunai, GG when minato has literally no place left to teleport to.
Not to mention kakashi caught the gedo statue before it teleported to madara, so I don't see how minato wouldn't lose a limb even if he has a few kunai left to teleport to.
& Shut up about...
The manga would be broken.
Obito with both his MS is literally invincible.
Long range kamui from the kamui dimension & in literally all directions at near light-speed? Nobody is escaping that.