Sorry for late reply.
"why going back to MSWindows age running GUI" you ask - well, if you want something like ISPConfig then you want a GUI, why else use it?
If you want to configure everything on commands that's fine, what I mean is don't use ISPConfig and configure via commandline at the same time. This is because ISPConfig does more than just add entries in vhost-file etc, it keeps everything together to minimize the administrative burden.
You have to choose, use a GUI (=ISPConfig) or commandline.

OpenVZ sorry I don't know anything about it.