Nothing has really changed with the sounds and music. You can still only play in Japanese or Chinese with English subtitles. It still doesn’t affect much since the combat is more or less separate from the talking. You can always pause the combat at any time to catch up on logs. As far as I can tell, there is no new music added to the game either.
The graphics still look the same overall, but there are some changes. The major thing that you will notice is that the battlegrounds have been greatly enhanced. They have added a lot more tactics and some of them are dependent upon the landscape. This means that they really needed to up the game on the landscape so that you can get the full potential out of your battles. Since you can now have children, you will have some new graphics associated with that as well.