There does not seemed to be any rule to whats enabled and what's not.
Package maintainer's and or developers seem to decide for them self
whether service
is enabled/disabled by default.
The proper way to do this is to only enabled system and network needed
services
for a functional and network connected system by default.
The rest of the services being enabled/disabled in firstboot either
individually ( advanced control )
or group together in a big buttons for more noob user friendly solution
For example Enable Blutetooh ( user clicks on that and all bluetooth
related services are enabled )
Enabled printing ( Cups and printing related service enabled )
etc..
Already filled an RFE for this and hopefully it will make F-X