I don't really understand why so many people think you have to freeze the track
you could
but you don't have to
you can bounce it to audio just by selecting the midi track and soft sytnth then bounce to tracks
as far as having the ability to go back to the midi file to make changes -- what I usually do is archive (hide) the midi track in case I want to change something later --
that way my screen stays a little more tidy and I can delete the soft synth and to keep things neat and have a lower cpu load
if I decide I need to make a change -- i unhide the midi track -- and pop the softsynth back in and make the change
I supose everybody has a different preferance in work flow
then again -- I only use soft sythns for drums and piano and nothing else -- so -- ehhh (Shrugs)