Now, we have "Browse local" button.
But when connecting to remote server, there is no such button, which is the pain, because using pools is not always suitable.
VMware have this opportunity since beginning. :)
The storage pool dialog is all we can do at this point, there won't ever be a real 'Browse remote' button that pops up a FileChooser, the capability just doesn't exist. If you have issues with libvirt storage pools/volumes, please file separate bugs.
But when working on the local host, we can go over libvirt and browse files directly. So why not to do the same, but over network? I think sftp support will be nice.