Sure there's bias in there, but I will say this, there are far more people living outside Miami than there are inside Miami. Being in Sunrise draws people from Miami AND from further north because it's a good central location.
I lived in Boca for a couple years, took me 30 minutes at most, tack on another 15 from people father east. Now from West Palm it takes around an hour. Bottom line is there's going to be traffic anywhere.
Put it in Miami and there's going to be more immediate traffic around the area and coming in from up north is going to be even more difficult. A Miami location is good for people in Miami and that's about it, likewise for Downtown Fort Lauderdale.
Sunrise is centrally located in the region and it has easy access. If you put it east, you're going to have to drive into the most congested areas in the region. Pretty much the only time I run into heavy traffic going to Sunrise is on Friday evenings, and anyone who uses the turnpike from where I am to the Sunrise Expressway is going to experience the same. Go through my posts and look at how many people live in that area. And that's ignoring everyone to the south of the arena who also have easy commutes.
Sunrise might not be the best for people in Miami, Fort Lauderdale, or West Palm Beach, but it's a damn good compromise for all three.