Show me scans of Sasuke doing legged Susano'o without naruto's help.Doubtful, considering that all of the Bijuus charged at Naruto at once and then they got knocked back. Don't see why they wouldn't do that once Sasuke activates the legged Susano'o in order to fight them. More so, if they stay back, multiple Enton or Susano'o Arrows can be released to kill those who stayed back or are trying to close in on him. Those who do manage to get close by some chance, get cut down in the same way Itachi did to the Hydra's heads.