I'd like to point out one thing that was overlooked in other answers and that is the target audience.
We already know that mini and micro B plugs are small and therefore in some situations they are also more difficult to connect. For example if the device is going to be put in a corner somewhere and not be moved much, full size B would be easier to connect blind, that is to say without moving the device so that the receptacle can be seen (as is the case with printers for example).
Some people also may have problems using smaller USB plugs. I know lots of people who can plug a full size USB cable without even looking but must get their glasses to use mini or micro sized connector. If you don't need the space, why risk having your user curse you for putting a smaller connector in place of larger?
Another point of interest would be the design of common cables too. Full size B cables are often easier to obtain in greater length than mini or micro cables and since device is going to be outside, that could be a bonus point.
Another point that needs to be considered for a device is the flexibility of the cable itself and the mass of the device. In some cases, if the mass of the device is such that a rigid cable may move the device, it may be a good idea to use smaller connector because they often use less rigid cables.