Dear Mariano and GNOME developers!
For me save session functionality was very useful too.
I can't understand why it was broken/removed.
We have hibernate and suspend today, but they can't be the replacement for DE session restore. Hibernate is not safe for modern SSD, suspend eats battery and I can't "restore session" with it after for example two weeks on rarely used laptop. Also suspend is not an option for stadionary desktop workstation (without UPS or battery).
With my 11 year linux experience I think, that GNOME developers are doing wrong things.
The first wrong thing was GNOME 3 with its Shell, the second was simplification of Nautilus (back, forward, parent buttons, extra pane), the third was gnome-terminal (removed tabs title).
If we talk about session restore it worked as expected only in GNOME 2.28 and 2.32 and of course KDE 3.5.
For now we have GNOME 3 with broken session save-restore functionality. For example in GNOME 3.4 as in Ubuntu 12.04 it does not work at all.
What users can do with it? We can switch to complicated KDE 4/5, or simple Xfce, MATE and Cinnamon.
But for example, MATE 1.18 is able to save and restore only gtk-based applications (so for example, Krusader is not restored).
I hope that GNOME developers can fix session restore problems soon and will not break/limit other things.
Good luck!