The Ubuntu Developer Summit has started this week and there were two very interesting sessions today: GNOME version and default applications in Ubuntu 12.04 Precise Pangolin.
It seems that Ubuntu 12.04 will continue to use most GNOME 3.2 applications by default, but use GTK 3.4 and pick up some new GNOME 3.4 components such as GNOME Games, Gedit, Eye Of GNOME and others. Some more important applications such as Empathy or Nautilus will probably stay on 3.2. Further more, Totem will stay on version 3.0 (like it is for Oneiric too) because Totem 3.2 uses clutter so videos won't work for everyone. The reason for this is that Ubuntu 12.04 Precise Pangolin will be released just a month after the GNOME 3.4 release (see the release schedule here) so there is not enough time to get everything ready.
As for the second session, most people who have attended the default applications session today at UDS-P have agreed to replace Banshee with Rhythmbox by default. However, decision is not final as there are a few things that need to be checked first (like Unity Music Lens integration, etc.).
The main reason for this is that Banshee still uses GTK2 and the GTK3 branch is currently blocked by some missing GTK# 3 features. And this blocks porting the Ubuntu One Music Store plugin to GTK 3 and it prevents it from working properly on ARM.
At the end of the session, it was even discussed to completely remove Mono from the CD since only Tomboy and Gbrainy would be using it, but no decision regarding this was taken.
Two new GNOME 3.2 applications were rejected from being included in Ubuntu 12.04 Precise Pangolin by default: Sushi (file previewer) and GNOME Documents. The first one doesn't integrate well with Ubuntu (buttons on the wrong side, no overlay scrollbars etc.), uses Clutter so it doesn't work for everyone and more. As for GNOME Documents: it doesn't do too much for now and also, this functionality basically already exists in Unity, through lenses and also, it uses Tracker and Clutter and is aimed at GNOME Shell.
PiTiVi video editor was proposed for reinclusion as default in Ubuntu, but was rejected because apparently the Ubuntu developers don't want a video editor by default. And if they would want one, OpenShot would have probably be chosen. So the final decision was: "it belongs in the Software Center".
Zeitgeist Privacy Manager was also proposed to be included by default, but no decision has been taken yet.