The switch from mini to micro makes perfect sense. The overall physical envelope IS a little smaller, plus this change represents a consolidation of connector formats in the industry. Several companies that had previously relied on proprietary connectors and/or a mix of types are now reducing that nightmare down to micro usb for the most part.

As for having both micro usb and a separate power plug, I can't speculate much on the benefit of any information, but given that it should be cheaper for a company in the long run to consolidate those as well, I'm guessing there was some sense to the decision to keep both.

And at your analogy.