All DEs we got now started with a small number of developers. Including XCFE and Gnome. Mate has the advantage that its environment is an already tested idea that works, so I doubt it will have issues getting new developers.
What I wish about MATE is that they fix their ppa. For some reason it needs strange tricks to install.
How exactly does gnome3 make life easier? I guess that after you install 22 extensions it starts to be a little usable, but that's not the same thing.No... the Gnome developers have been trying for years to save Gnome 2, but in the end it was too inflexible to be retrofitted with the newest features to make life easier. So they binned it and moved to Gnome 3.