I don't work for SAP, so this is my experience from the field. :-)
74 was the first good revision in SPS07. 71 got pulled and 72/73 had defects that meant that my customers all moved off them. Also SPS07 didn't get updated client tools until 74.
80 was good and 81 better. So there are plenty of reasons to upgrade!
But in general, software bugs get fixed in newer versions. Given the functionality you desire came in SPS07, it shouldn't be a major surprise if it's not functioning four weeks after release which is when Rev.72 came out.