hello
you have a default zone then so indeed all host should see the luns (better to have a zone ofcourse)
what image you used? vmware or vendor customized?
i solved the problem after upgrading to ESX 5.5U1 by logging into my FC switch and configuring the ports again where the server is connected on.
that did the trick for me. after rescan i could see my datastores again
hope this helps you