Mike, the retirees are not the ones turning Florida blue.  It is the minorities that are turning Florida blue. That is why there is such harsh voter suppression here.  The voter turn out in Florida was very low for 2014.  You have to go all the way back to the beginning of WWII to find the same low turn out.  People in Florida are not going to fight the system to vote for former Republicans turned Democrat.  They will get out and vote in a national campaign for a Democratic ticket. Even thought it effects the poor Republicans too, there is enough upper and middle class to carry the Republican vote.  This is a class and economic war going on against voters. 

The Florida Supreme Court has ordered the legislature to redraw the district's map. They are refusing to drag this out past the election. Now the court has to do it. They know if the Democrats get the upper hand in just a few districts that will be an inspiration for people to get out and vote. I am in a state senate district that is only a mile wide cutting through my county to gather up all the AA vote in Sarasota to add to Tampa.  I am disenfranchised because I live on the wrong side of the street.  They moved my poling place to the Sarasota county line.  So why should I even bother to vote in a mid term?  The 2014 didn't have a Senate race and Crist was a former Republican. 

A better measure will be the Patrick Murphy and Allen Grayson Senate primary.  Murphy is a former Republican turned Democrat from a very red district  If Murphy wins that means the minority voter is sitting this one out and the state swings Republican. 

Rubio isn't much a factor in this.