You could pretty much call this one finished at this point and most people would be happy with it, although I certainly understand having a more completed vision in your head. I kind of like the slight roughness to it at this point.
FINISH HIM OH MY GOSH HE LOOKS BEAUTIFUL EVEN NOW!! lkjasdofajsdlfkj SPOOOOOOOOOOCKKKKKKKKK!
I love Star Trek, and think this new casting for the original characters is fantastic - especially this dude!!! <3
I didn't notice it at first, but... Is this Sylar? After I looked at it, and then went back to the thumb, I suddenly realized the features were a little familiar.
(...and I don't remember what Spock looks like. But I did think I remembered hearing that the guy who played Sylar was in a new Star Track movie)
So, if that's who you're doing, then it looks enough like him to be recognizable, despite not being finished.