Akainu is surely not getting Blueno'd, that much is sure but are we that sure Oda is not going to go the Sabo route?
Sabo inherited the Mera mera and thus Ace's will,it is Oda's style to atleast involve Sabo in Akainu's defeat.
So I think it will be Luffy and Sabo vs Akainu at the start of the fight,then Luffy goes on to more important stuff and Sabo finishes the job.
What do you think?