I think one more way to get ISPConfig more popular is to get server providers (like hetzner, myLoc, 1&1 etc.) to provide ISPConfig as a panel in their default server images like they offer plesk, confixx (and often cpanel/WHM).
I tried to introduce ISPC to a server provider few days ago but the reply was "this panel is not requested by our customers, so providing it as default image is too much work for us". They said they might do it later, as confixx will be discontinued at the end of this year.
I'll try to bother the server provider again from time to time
maybe it helps.
What I think would help to reduce inhibition threshold would be a completely unattended setup.
Currently there are some questions you have to answer even during basic install. Maybe the setup script could be extended for unattended call with mandatory parameters on shell - using all the default values without having to press enter, like:
php install.php --unattended --dbhost="localhost" --dbuser="root" --dbpass="rootpass"
Update: I just got a reply from a provider basically saying: "it is on our agenda, but do not expect it short-term"