Will criminals go to "Open Carry"? Absolutely not.
So what about average citizens and 'Open Carry'? I am hard put seeing 99% of most people flaunting a pistol. Who is going to walk into a 7/11, or a hospital, or a Wal-Mart with a Colt 1911 on their side. All that will really happen is stores will put up 'No weapons allowed' signs.
What you will see is, citizens taking a gun from their car in a self defense situation, or a pawn shop owner walking his reciepts to his car sprouting his 45 auto.
The biggest opposition is coming from LEOs. In this youtube clip, the Sheriff spokesman says if his men encounter someone with a pistol, sooner or later there will be 'bad outcome'.
YouTube - Open Carry Debate - Florida House of Representatives - 3/24/2011