MySQL workbench is unable to establish ssh connections to remote hosts if =dev-python/paramiko-1.15.1-r1 is installed. If I downgrade paramiko to 1.10.1, it works. I do not know if the (oldish) =dev-python/paramko-1.13.0 works with this version of mysql-workbench, nor if the (old) =dev-db/mysql-workbench-5.2.47 works with the current version of paramiko.. I have not tried. This thread discusses the problem (albeit on RHEL/Cent, Fedora and Arch.). http://bugs.mysql.com/bug.php?id=75075
This should be fixed in mysql-workbench 6.2.3-r1. Given that paramiko 1.15.1-r1 is now stable I should probably file a stable bug for that version.
I have created bug 541304 bug that requires additional dependencies to be marked stable so it can't proceed right away.