Hello Max,
I went ahead and tested this on Fedora 27 w/ NetworkManager 1.8.6-1.fc27 and was able to get it working. A few things I noticed:
Starting the VPN with SELinux enabled results in a number of alerts. Mostly for the sysctl source process. This is to be expected as you mentioned you were testing on Arch. If this ever ends up getting packaged for Fedora the policies can probably be added to the RPM.
The DNS field under Identity does not currently function. I am not sure how you want to handle this field as NetworkManager has their own DNS field under the IPv4 tab in the GUI.
The Endpoint section of the GUI only accepts IP addresses and not FQDNs.
and the last thing I noticed: the Private Key section is required. This breaks functionality if you were to have your private key stored in a password manager. This is solvable by just pasting a properly formatted key (I just used my public key) into the field and adding a Post Up script to grab the private key string.
I am going to keep playing around with this and possibly work on packaging it into an RPM.