Not mentioned so far but FMS2 also has the following:
Option to display ETP on route of any two chosen airports;
Vr bug on the PFD;
Allows you to see TCAS targets on all ND scales; and
Step climbs (can't remember if the FMS1 had that).
I'm sure there's more.
Some FMS2 upgraded aircraft have an increased Recommended Max alt increased from FL390 approx to FL398, which allows the A320 to operate at FL 12,000m metric level (FL394).