Let's not forget that the choice of venue is crucial to each fighter also.
Chuck needs the fence. It is one of the most critical parts of his takedown defense. You know how he squirms his way back up it. Chuck would be foolish to fight in prides ring and Wandy wants the ring so Chuck will have a hard time bringing the fight back to his feet if he gets taken down.
That probably has a lot to do with the posturing both organizations are doing.