short and quick:
turn Bunshin (once the required lvl is reached) into Kamaitachi, but give Kamaitachi the added effect of Bunshin, reducing Button Presses to 1 instead of 2 (as it is in 6.11)
Reason: you gonna Press Bushin twice anyway, so reducing redundancy in that regard is preferable.

and a slightly bigger request:
make Hyosho Ranryu available at lvl50 with Kassatsu, for better muscle memory development, maybe weaken Hyosho Ranryu slightly above Raiton's potency and give it a Damage Boost Trait at lvl76.
Reason: Once you hit lvl76, you gonna do Hyosho Ranryu from that point on in Single Target Situations, so why don't introduce this concept with the Unlock of Kassatsu itself.
Overall I adjusted to the NIN Changes quite well.