You've picked a very touching song, that's for sure. In addition to it being very slow tempo for a dance, it's also pretty long -- like about five minutes, if you are using the original Broadway version with Idina Menzel and Kristen Cheneworth. Professional dancers would figure out some type of contemporary style or steps to flow through that song. I have seen that done in dance routines or shows, especially just after Wicked went on its national tour.
But it could be difficult in a wedding dance setting. If the words and the message are what you are looking for, you can always simply sway back and forth slowly in a box pattern. Otherwise, you can look for other danceable options probably by just searching for Father-Daughter wedding dances on your search engine.
Obviously, a waltz is a great choice to look for.