Imo Ubuntu deserved to lose its users when they switched to Unity, not because Unity sucks (it does) but because it's unacceptable for a newbie-focused OS to rug-pull its entire GUI like that for any reason. But it's still #1, so realistically the leader is going be either Ubuntu or something corp-supported like SteamOS.
I don't think this is a problem at all. I tend to install Debian from the command line (Arch-style), but from what I remember GNOME is the default DE. DEs are largely a matter of opinion, but I find GNOME to be more polished overall. I do use a few extensions however to recreate a desktop-centric UX (Dock, boot to desktop and a few other tweaks).
I mean I really do love Debian, if not OpenSUSE I would be using Debian now, but it's not a great distro to suggest for absolute novices.