I think it would cost too much for a relocation.
If it's getting replaced..one would have to ask, would it really be for Potter? Take 5 was shortly during the time before Potter, and they would have to go through that effort again to not only relocate that, but redo the staff infrastructure in that area of the park.
Methinks, if Waterworld is leaving sooner than later; it's for something completely different.
Edit: To put it to perspective, it'd only have half of the size that HMCMA has, and that's even including Take 5 Grill and various backstage that'd need to be relocated/demolished for them to go forward.