Actually I think the casting of Felicity Huffman is what sunk the movie for me.
For nearly every transwoman I know, a major battle in their transition is trying to get a male body, with all it's bulkiness, hairiness, lumbering, and deep-throated growls to play a female role.
With Huffman, a female bodied person, that struggle just wasn't there. I could see a male-bodied actor playing a trans woman in transition, but that female bodied actress simply didn't bring the story home.
Interesting that I felt that way at the time, even though I had zero knowledge of transgender and had not yet met a transgender person up close. Now that I'm going through a transition myself, I'm all the more convinced.