I know, that the Samsara of Heavenly Life is able to resurrect either all the individuals recently killed, or a single person from long ago. I know also, that this jutsu it's different from the Edo Tensei, since "It seems that this technique does not need the original body for the owner to be brought back, as Madara's original plan consisted of Obito reviving him at a time where the original body would have decomposed."
So the question is: does this technique have a weakness, or a time limit, after which you can't use it, or it's flawless?..If that's the case, could a Rinnegan user revive e.g. The Sage Of The Six Path?