Florida from June through October is a deal breaker for me. The heat through all of it, and the hurricanes through the later part of that time period are something I won't pay thousands of dollars on a vacation to deal with.
Now as it relates to masks, during this period before there is a vaccine, effective treatment, and/or herd immunity I wouldn't go if they DIDN'T mandate masks.
As most know the mask (other than N95 masks) are not designed to protect the wearer, they're designed to protect those around the wearer should that person be a carrier. And as noted by others while some will not wear them effectively (i.e. some will still continually adjust them, touch their face, and then touch surfaces etc.) many still would wear them effectively if mandated. Plus I can somewhat protect myself by mindfully reducing touching surfaces, not touching my own face, continually washing my hands etc.
Now that all being said, the main deal breaker for me would not be masks, but if other key operational changes would negatively impact my experience. Things such as reduced ride capacity (i.e. 1/2 filling ride vehicles), some attractions not running at all (if they can't effectively be reconfigured to operate safely), all rides going virtual queue etc. All things being the same but only difference being wearing a mask, I'd go.
But by the sounds of things, masks will be the least of the negative operational changes that would have me hold off from going.