Fixes where quests could be more clear, added banter, etc would be more serious. Things added are likely the same. Overall, the writing will probably be a little more serious, but AFAIK there was no concerted effort to change the tone.
I am aware of some additions and changes, but have not played through the EE yet (other than to check if a couple reported issues for D:OS were fixed in the EE). I'm waiting for a certain build to be done to start a 'blind' playthrough in the harder difficulty mode (others have already been testing and given feedback on the current balance).
