I doubt Sasuke can reach that level again without the Bijuu, while mastering the Rinnegan will vastly improve his powers, the Rinnegan can only do so much.
Also he openly said that Indra's arrow was the strongest move in his arsenal, it was created by combining the power of the Rinnegan, EMS, and the Bijuu, how can just mastering the Rinnegan compete with that.
Also he openly said that Indra's arrow was the strongest move in his arsenal, it was created by combining the power of the Rinnegan, EMS, and the Bijuu, how can just mastering the Rinnegan compete with that.