take a look at the oro's kusanagi like this..so far we've only seen him uses kusanagi's abilities...which is extend to immense proportions...and also due to oro's kusanagi abilities to be able to cut through almost anything..i think it is just logical to keep oro's kusanagi just the way we've seen it in the manga..cause put it like this...the ability to cut through almost anything..enhanced by chakra would make the kusanagi almost unstoppable..only the tailed beasts will be able to block it since oro's kusanagi is not able to pierce naruto's 4 tail cloak...this will place the other rpers at a disadvantage cause not everyone own oro's kusanagi and only 9 rpers has the tailed beasts..and from the manga itself...i dont recall seeing oro charging his kusanagi up with lightning/fire/water/wind/earth/ice etc chakra...we've only seen oro controlling the kusanagi telepathically and using its abilities..again..i think we should stick with what we've seen from oro's kusanagi as to prevent overpowering.