Not sure if I'd describe the backs of the O2 and O3 as cold. Maybe because I live in a hot area.
. Would I like something more grippy? well maybe. Its never bothered me. I don't use a cover on it. I am using a hand strap now and its perfect for me.
It feels and looks like a premium device. Although it might be nice to have the Voyage back on it. Its more grippy I think. But it was actually more slippery for me because I didn't have enough bezel to grip it while using the buttons. It slipped out of my hands because of that. I might put a handstrap on it too to see how it goes. I wish the buttons all were like the keyboard, on the edge. No smudges and so easy to use.