I'd be interested in having RTC onboard
# The newer Micro-USB receptacles are designed for up to 10,000 cycles of insertion and removal between the receptacle and plug, compared to 1500 for the standard USB and 5000 for the Mini-USB receptacle. This is accomplished by adding a locking device and by moving the leaf-spring connector from the jack to the plug, so that the most-stressed part is on the cable side of the connection. This change was made so that the connector on the less expensive cable would bear the most wear instead of the more expensive micro-USB device.
There are only a couple of reasons that I can see the justification for the mini-USB connector:1) Availability of power adaptors/wall warts with a mini-USB plug output.2) No worries about a shield "shorting out" with the mini-USB jack.