I've been thinking this issue over, heres some of my (slightly contradictory) thoughts:
The problem with 'transgender man/woman' is that the word puts the majority of the emphasis on what you were, not what you are. It basically says "was once a man" or "was once a woman" instead of stressing what you are NOW.
When people move on from something that they were, they often get the title "ex" or "former" prefacing their old title - i.e. ex-cop, ex-girlfriend, ex-friend, former teacher, former manager, etc. The majority of these have a positive connotation.
Some things do not get an "ex" or "former" applied to them - you don't get ex-murders or ex-rapists. It seems when something is really bad, you're never allowed to move on from it.
The exception to this is ex-convict, which shows that you may have moved on from offending, but still references your bad past.
However I don't think 'ex-man' would help any more than 'trans woman' since it still places the emphasis on what I used to be, which isn't positive.
So how do we refer to people in new roles or positions? New employee? New manager? New person? Or just plain newbie?
As trite as it sounds, 'New Woman' or 'New Man' have far better connotations for me than 'trans woman' (ex man) or 'trans man' (ex woman).
'Neo Woman' or 'Neo Man' might also be an option and it mirrors the proclivity to call post surgical vaginas 'neo vaginas'.
Anyway, those are my current thoughts on the subject.