There will be an enlarged auxiliary nav deflector in the same location on the bottom of the saucer where the auxiliary deflector was on the original Galaxy. At the front of the saucer, is just some random graphics I was trying out...sort of like the paneling on the nose of the Defiant class, though it's not working the way I want it to right now.
I thought about going with a Intrepid style auxiliary deflector on the upper side of the saucer, but ultimately decided against it.
The captains yacht has been replaced with a dual quantum torpedo launchers and eventually it may be expanded into a larger sensor platform/dome, reminiscent of the old sensor platforms seen on the refit Connie and Excelsior.
I'm still very early in the development of the upgrades, so at this point I'm still trying to get down the basics of the Galaxy Class itself. More changes/upgrades will become apparent as it progresses a bit more.