When the state special prosecutor's office filed for second degree murder, it was a politically motivated, public opinion assuaging move. It quelled a huge out cry in Sanford and across the state. With only Zimmerman as a full witness, and little physical evidence, second degree would have only been met if people on the jury had actually kept in mind all of Zimmerman's odd actions, and self-contradictory statements in his incident interviews by the detectives. Zimmerman even had Trayvon saying crap about as believable as lines from a 1960's Dick Tracy comic book.
Second degree under FL law is very strenuous and frankly reads as just a hair's breadth below first degree, premeditated murder. I actually suspect the decision to pursue second degree was a ploy to help assure Zimmerman was acquitted, in that, the jury is more likely to also dismiss the manslaughter option after failing to agree on all the stringent points of second degree.
Mark O'Mara is on my all-time Biggest Dickweeds list for his post trial spews about what if Zimmerman was black, and Trayvon died-kids-die-of-cancer-too. I will fucking slap his dentures* out of his face and crush them under foot if I ever meet him in person.
*I know the signs; got a full set myself.