I agree that Linus is a luminary.
I don't agree that his opinion regarding UI is worth a damn.
I would be like taking fashion advice from a textile industry engineer.
His skills are orthogonal to UI, and his decisions were bad in the past (KDE!! WTF!?) .
I understand XFCE might be better suited to him, mainly because he won't need to learn new tricks.
For the general public, Gnome Shell or Unity are great, they are a lot easier to learn from scratch, more discoverable, and suited to actual newbies, a very important audience to take into account when you have a single digit marketshare.
For experts, they are also great, because they reward knowledge, are searchable, and save screen real estate.
Most importantly, they are designed by specialists, with the user in mind, and actual tests, with actual users.
A kernel developers opinion is not that relevant here.