Is the seal weakening on its own or Naruto is getting better in controlling Nine-tails chakra and tranform quickly?Then agian they said that anger is the trigger and we all know he has a short fuse. It looks like his body is covered in blood.
Like Jiraya said the nine tails chakra damages his body which is followed by quick healing, is shortening his life span. Will he live to be a Hokage? The yougest Hokage maybe?