i dunno if anyone thought of it.. but how about all three eyes together soo..
mandara: for ems and countless abilities that come with it such as susano and more we don't know about
Sage of 6 paths: being able to master all elements and still being able to take down any kyuubi or watever bi
someone with the buyakugan such as neji or hinta or whoever. The 3rd person isn't as important with power since the previous two or the strongest shinobi but more so for the eyes to see distance and everywhere around them.
mandara: for ems and countless abilities that come with it such as susano and more we don't know about
Sage of 6 paths: being able to master all elements and still being able to take down any kyuubi or watever bi
someone with the buyakugan such as neji or hinta or whoever. The 3rd person isn't as important with power since the previous two or the strongest shinobi but more so for the eyes to see distance and everywhere around them.