you're reasoning has too many holes in it.You're not comprehending the fact that Kiba's attack is rotational, just like Neji's. Your statement is baseless until you can show me a single instance in the manga where Kaiten repelled another rotational attack moving in the opposite direction. What Kiba is essentially doing is putting brakes on Neji's rotation, with a counter rotation of his own. Garoga packed enough force to put a huge dent into a Rashomon gate back in part one. War-Arc Kiba can obviously do even better, and perform Garoga x2 with the addition of shadow clones. Nejis is toast.
nejis rotatial force can't be ''countered'' unless his shield is overwhelmed by mass/energy or his body is hit.
in comparison, kibas rotational force alone doesn't protect his center of mass(body) like nejis borg does. he can't even stop him self from losing traction & staying grounded let alone maintain a straight line to hit neji.
and if kibas attack comes from mid-air, instead of tracking across the ground, its completely useless
and even if it were an even technique comparison, i'm not sure why U think kiba has an advantage when his linear motion causes drag & has already begun to decrease his force, only to be accentuated by the shield.
neji is anchored, kiba is not. kaiten won't turn off when kiba penetrates it. it won't pop or poof when hit
the barrier is not rigid like its opposition(kiba or a rashoumoun gate for that matter).
it is fluid & volatile.
its rotation gives it repelling power, yes.
but dont ovelook that the superior mass of chakra is also pushing outward, spinning or not(like bodyblow). so there is actually 3 differnt forces for kiba to overcome, vs only 1 for neji
so its a sphere of *anchored spin+superior mass/energy+friction(chakra-blowback)* vs a disk w/ *un-anchored spin*