I dunno, I think Mary's seen her time in the sun. The reboot flopped horrendously, and the younger generations don't seem to really care about her. I'm 31 years old, and only about 1/4 of people I know my age have seen the original Mary Poppins movie. I only saw the Broadway production. As much as the World Showcase needs rides, I just don't think Mary Poppins is the right IP for it. Not to derail this further, but I'd build an updated Peter Pan's Flight in the UK, and repurpose it's footprint in MK with a Tangled Ride for synergy with the bathrooms.