I am using Hestia 1.9-alpha on production servers and have installed it without php-fpm.
After going through the whole project (excluding the web interface), I find it the most convincing to modify the installer such that it will merely install the main Hestia Control Panel without the webservers.
My suggestion is that the HestiaCP installer should install the Hestia Control Panel without any webservers. Later, just like php additions and changes, one can later execute certain scripts to install combinations of apache2 only, apache2+nginx only, or even apache2+nginx-phpfom set.
Like this, one has always a stable and a minimum version of Hestia Control Panel, which will definately work and serve the purpose.
I have always objected to having a GIGANTIC INSTALLATION PROCESS, which is over ambitious. This works. But this has many drawbacks too.
If the installaer installs minimum version, people can later change it and test it out. Further, adding other multiple recipies of installing other webservers will also become an enhanced possibility, once this area is developed.
By doing so, the install process will open a modular approach of HestiaCP to install webservers at a later date.
This can be achieved later when the user selects one webserver and installs it. At this time, one could choose, if one wants to install webmail at all or not.
For example, I do not use the default webmail installation at all.
If it is possible to choose webmail then it will also open door to install multiple webmail scripts, like Rainloop, Roundcude upon selection.
Like this, HestiaCP goes to a different level to become modular!