You can download the current ispconfig debvelopment version at any time from our git server at http://git.ispconfig.org/
and jump on not-final/maybe-bugged/work-in-progress/at-your-risk 3.1 from git http://git.ispconfig.org/ispconfig/ispconfig3/commits/master ?
There are a lot of users at facebook and twitter as well that don't contribute If someone has not enough interest in a software project to use the GIT repository of that project to commit there then he won't contribute anyway.
Do you have a date when you expect 3.1 to be done? And would it be possible to have php7 be set up too by ispconfig install script as in the tutorial?