OK, I get what you're all saying, but I live in greater Hollywood and many of my friends are actors, directors and producers. I know that there is a great deal of money at stake here, and if this movie bombs, there will be people who find themselves quickly out of a career. One tried-and-true way to help a movie along is to cast it with household names. Once you get spendy on cast and crew, a studio must market the film accordingly in order to ensure it generates enough revenue to at very least cover itself.
Eddie Redmayne is an Oscar-winning actor. Alicia Vikander is on her way to being the next big thing (See Ex Machina!).
Had this movie been done on a low budget with a trans actress and limited release, fewer people will have been educated about the plight of transgender people. It was sad to see the movie Tangerine screened in Hollywood at one theater for one week. I think we deserve a bit more exposure, especially now.
Also, I like watching movies where people can actually act. So far I haven't seen a trans actress that was up to snuff. Perhaps that will change soon as well.