This topic has been raised a couple of times during my time in these forums, particularly in SLF forum. So the search function might find some.
In short, it is the take off that people are said to not like. But I think a bigger problem is that - if a carrier decides to switch to rear facing for saftey reasons (which seem well founded) Pas will be asking, "Why did you not do this 30 years ago? You don't care about us do you?" and similar.
For myself, I did travel once in the Trident with rear facing during an experiment in the mid-70s and I filled in a response form saying that I thought it was fine.
I do not expect any carrier to introduce this wholesale.