The path abilities of the Rinnegan are all based upon the buddhist idea of reincarnation. But they also all show god-like abilities that almost no other possesses. Shinra tensei, mechanization, infinite absorption, soul removal, and Resurrection. However one of these abilities seems less then god-like. The animal path. Okay the rinne summons that pain uses are pretty powerful, but they are still basic summoning and just an extension of the 6 paths technique. What is so godlike about that?

But what if, the summoning aspect of the animal path is just a watered down form of a greater power?

Summoning is the most basic form of space-time ninjutsu, and since the Sennin is the father of all ninjutsu, it is possible that the animal path was initially not just the summoning technique, but a full blown space time ninjutsu, possibly on a greater scale then even kumoi or ftg. This also makes since, due to Obito- an ms user having a space time ninjutsu. since ms is an from the rikudo, this seems logical.