The reason they have free refills at BWV and not at OKW is simple... they know that with the marathon walk to get from your room to the lobby at BWV, no one will be able to take advantage of it anyway! They sell you a $10 mug, but put the refills 26 miles away to keep people from getting to them.
They'll never have free refills at OKW because it is just soooooooo convenient to go outside to your car that is parked 20 feet from your villa, drive to Goods to Go, park it, walk another 20 feet to get your refill, walk another 20 feet back to your car, drive it back to your villa, park it and walk the final 20 feet back to your villa. With all of that super convenience, Disney would definately lose money on the free soda thing!
Lisa