Change the default configuration options to better reflect the changes in the modern connectivity world
Delivery receipts are already there for years, though the user still has to enable them by hand in program preferences. They should probably be enabled by default, since it's almost a must-have feature to tell if the other side has at least received the message or not.
Nowadays one's presence means almost nothing, thanks to offline message delivery, XEP-0313 and push notifications. At least the first one on the list is enabled almost everywhere, so the user doesn't even have to care about his/her buddy's presence. This means offline contacts can safely be shown by default, since messages are delivered anyway.
Both of the changes are only usability-related, brushing up Gajim's UX for new users.