There are a whole bunch of things that I dislike about the options for the ending, but I still think that letting us recruit or save both Orpheus and the Emperor would undermine it in a way I'd also find unsatisfying. But I do wish it were possible to persuade the Emperor to let us free Orpheus and there then to be some dialogue with both, even if Orpheus refused to work with the Emperor and we were then forced to choose. I feel that siding with the Emperor over Orpheus would be an option for more characters if we could talk to Orpheus and give him the option to cooperate first, rather than condemning him without even speaking to him.
I also agree that the Emperor leaving in a huff as he does is really jarring, and would much prefer there to be a showdown there and then if things didn't go his way. Especially as I found the fight with him in the finale a bit of a damp squib, given you can (and probably should) just ignore him and head for the brain.