Gnome used to be the default desktop environment in Debian for several years but in November 2013 they switched to Xfce. It didn’t take long, there wasn’t even a single release which featured Xfce as default DE and now they’re switching back to Gnome. Joey Hess is the one who performed this change. He said:
Some desired data is not yet available, but at this point I’m around 80% sure that gnome is coming out ahead in the process. This is particularly based on accessibility and to some extent systemd integration
As far as accessibility is concerned, Joey mentions that GNOME and MATE are ahead by a large margin while other desktops still need significant upstream work. As for Systemd, GNOME is ahead of all desktops which are “stuck paying catch-up to ongoing changes in this area”.