User blog comment:Tekkphreke/Theory on Ukitake's Bankai/@comment-5147109-20130912162143

To be more specific on this, I believe that his Bankai ability may have certain types of restrictions on what it can replicate, for example, I'm sure that he would probably not be able to replicate the abilities of say Senbonzakura or Heinako as they both involve completely removing the sword itself from the equation, however abilities like Hiyorinmaru or Benihime it would likely be able to replicate those abilities.