Yes, the chaos factor is an interesting thing. But like everything, it has to be in it's right amount.
Not too much, not too few.
I think that cuting the free-for-all zone down by 9 it's a very good choice. The result would be a zone that still would be quite big, but not too big in comparison with the rest of the map, so it would be like the right balance
A couple of swamps could be interesting, or maybe a river or a mountain chain (don't know Florida's geography, so I am not sure if there exists a river or a mountain that can be represented in the map as impassable).