AFAIK the decision has been made to use Mate. I think this is a good
decision, and I might start recommending Trisquel 8 to new users switching
from Windows/MacOSX (I currently recommend Mint as a stepping stone from
proprietary OS to fully libre GNU/Linux).
GNOME 3 is great, but in most metrics I've seen it's the third most
resource-hungry DE after Unity and KDE. Even in Fallback, it probably still
uses more resources than XFCE, and definitely uses much more resources than
Mate. There's a good blog piece from 2013 on memory usage of DEs here,
complete with a bar graph:
https://l3net.wordpress.com/2013/03/17/a-memory-comparison-of-light-linux-desktops/
