He's talking about systemd. That's the only real architectural change that affects the server installs of many desktop/server distros.
Not the only one (nor is systemd entirely desktop driven). Before systemd ate it, DBUS gave us the session bus, and many applications would only ever use the session bus, and could not be used without a login (usually X) session, even if they really didn't need it. In many cases one had to at least recompile and sometimes even hack the source to change it to use the system bus (or disable DBUS support entirely.)
Then there are the various attempts to unify configuration across large suites of applications, which usually devolved into a system that was XML or some such crap just on principle and hence tedious to manage from the CLI/text editor -- but the authors of those didn't care as log as they had a control-panel workalike GUI.
And there were lots of individual groupware oriented network services that seemed to think they had to be intrinsically tied to a desktop login to work.
As to TFA, I doubt there will be a convergence onto a single "thin" distro, since so many levels exists allready ranging from OpenWRT/busyboxish systems all the way up to "server" editions that are really quite bloated.