Ruben has indicated that there will be a graphical installer for Trisquel
8.0. I hope that Calamares could also be considered:
https://calamares.io
Calamares aims to provide a universal means of installing a variety of
Operating Systems, so that one would not need to keep learning a new method
every time switching from Parabola to Trisquel, for example.
I particularly like one feature in Calamares, which is used by Chakra
GNU-Linux: The ability to simply and easily reuse a particular partition for
the installation. (Chakra is non-free, but the beauty of this facility has to
be seen!)
Please look at it and see what you think.