"Wizz have just shown a willingness to operate from lesser airports such as DSA".... Wizz have operated numerous daily flights to/from DSA for a number of years (as they do from LPL). What is new is the based aircraft at DSA. If Wizz were interested in SOU and there is the market for them that you seem to infer, they would have put 'their toe in the water' with non-based aircraft by now.