The way I see it, how much is your time worth? Personally I'd prefer to go enjoy all of the mazes and then get out of there and maybe even to bed at a decent time. If you want to spend your evening waiting in lines (which honestly tires me out faster than anything) and not get home until way after midnight and NOT see all of the Haunts... well then who am I to say anything.
From here on out, Saturdays will be nuts at Worlds of Fun once the "WITCHING HOUR" starts.
Just warning you. Also if you DO come and it is after 4pm, go park in the Oceans of Fun parking lot instead. A lot easier in and out traffic. Trust me.