Thank you for your request. The right click menu of the Synchronize view already contains an Expand All action. We will consider adding two icons, Expand All and Collapse All to the toolbar of the Synchronize view.
We added the two actions on the toolbar of the Synchronize view. You can see them in the current version of the SVN client, that is version 2.6 which works with the same license key as the other 2.x versions.