The reason Kishimoto didn't have a BSM Naruto vs EMS Sasuke

[Jokule67]

You know one could easily say Rinnegan was needed for Narutod superiority with Ninjutsu attacks.

Also Sasukes PS may only have wongs because of Six Paths Chakra. When he used it with the Kyuubi with EMS there were no wings.

Also, the power scale has always been somewhat leveled. However Naruto had the edge with BSM.

 

[Sasuke The Solo God]

Their still equal at this point. PS cloaked with Amaturatsu stops all senjustu attacks.

It was only when sasuke gained the rinnegan that he entered his own league