GNOME 3.12 is totally about GTK (+apps) and Wayland, and all those new things in GTK 3.12 is mostly a work of Matthias Clasen. There are more guys of course like William Jon McCann, Carlos Garnacho and others, but Matthias deserves most of the credits.
I am previewing some of my favorite features (for users), but I skip some to shorten the video. Video quality for once more is bad, coz I was running some queries in a 3.5m documents database, and I couldn’t stop it. I also used Shell 3.10 session, because it wasn’t a good time for me to having any crashes :)
Nothing new, I just put them all together in a video :)