I’ve been using iptables for more than 10 years and I don’t really like firewalld approach.
When I installed my Fedora 25 workstation, I installed a GUI-less Fedora Server edition, and installed i3wm on top of that.
One of the steps has been to disable firewalld and replace it by iptables, see doc here. The doc is outdated (for Fedora 19) but still relevant.
After every reboot, firewalld always started in favor of iptables.
It is due to a dependency on rolekit.