All I can say is don't be fooled by GNOME's default theme, Adwaita. On a computer, Adwaita looks just as bland, but that also means it doesn't distract. GNOME can do a lot more visual bells and whistles than that, it just doesn't do it by default. I'm pretty sure Purism will create a theme, or use an existing one, that's a bit more visually interesting. Right now they're only showing off the functionality, not the looks.

Edit: come to think of it, it shares a sizeable amount of resemblances with the Harmattan theme.