I guess it would be very beneficial to have the option to restart sync (force sync now) for all folders in the context menu when right-clicking the owncloud icon in the task bar. The option could be directly displayed below the “Pause synchronization” option.
Actually, I guess the “force synchronization” option is much more often used than the “Pause synchronization” option, as it is used to trigger an update immediately if you have just changed a specific file that shall be synced to another device for further usage. Currently, one has to open the client, look for the folder containing this file and force the sync for that specific folder.
Moreover, it is also often the case, that some file (like a notebook, which is saved frequently) is changed during sync, which leads to the case, that this file is not automatically synced anymore, until owncloud is restarted, or the user forces a new sync. In this case, it is also a benefit to be able to simply right-click the owncloud icon to force a new sync.