Sticking to LTS releases was actually the worst way to do this as it meant catching 10.04 which was effectively a "one off" UI, resulting in two changes to the UI rather than one big overhaul.
My mother started off on 8.04 LTS. When upgrading to 10.04 LTS the window buttons changed sides and there was a new theme (this is enough to throw many users). When upgrading to 12.04 LTS there was a change from Gnome to Unity.
My mother now chooses to use a Mac because she was fed up with her computer "changing" each time I updated it. I doubt I could convince her to try any Linux distribution again - there are no perceivable benefits for her.
I feel like 10.04 was a real high point -- I was running it the desktop for a long while, and the netbook edition was great on smaller screens. The netbook shell was a one off, it only was 10.04, and I think it's nearly impossible to install now. Unity was a descendent of it, but (IMHO) going the wrong way.
You can always install a different windows manager and stay with a Gnome-like interface (Cinnamon). I don't see what is the big issue with that. There are tons of options on Linux, that's the whole point of the system, it gives you choice.
My mother started off on 8.04 LTS. When upgrading to 10.04 LTS the window buttons changed sides and there was a new theme (this is enough to throw many users). When upgrading to 12.04 LTS there was a change from Gnome to Unity.
My mother now chooses to use a Mac because she was fed up with her computer "changing" each time I updated it. I doubt I could convince her to try any Linux distribution again - there are no perceivable benefits for her.