VNC (screen sharing) stopped worked after enabling filevault2
I can confirm that FileVault 2 does not disable VNC client or service. I use encryption on all Macs and VNC between them frequently (both at home and at my F500 employer).

Can you be more specific about how it is failing? Do you see "Share Screen" option in Finder? Have you tried via Finder > Go > Connect to Server? Does it time out or give an error message?