User blog comment:AYET/The Mera Mera no Mi and Doflamingo/@comment-3425840-20130301174245

Everyone knew Luffy was alive, remember OX bell incident?

Aside from that, well he can'y eat it himself as he is a df user (almost confirmed).

I think he does not want to give it to a subordinate because then that subordinate might get too powerful to deal with. Example, Vergo with mera mera no mi would give I think almost everyone a run for money.