While it is nice to be able to adjust leave for partial days, there really is no way of the employer tracking when the employee will be gone on partial days. As a smaller school with the need to find substitutes, this feature is key to our use and utilisation of the product. The Google Calendar sync functionality is also great but if there are no times associated with the leave requests, then it really doesn't fulfil our needs.
I would add the possibility of setting also the out of office in Google only for the period specified, i.e. from 2 to 4 pm and so on.