Yikes, sorry Thrawn...
...and most profound apologies to Sir Sean Connery.
I stick with Clooney for Kirk, because the character is a womanizer. I don't know that Willis can carry it as well.
For Bones, who's that dude that plays Frazier's dad? Somehow I can see him saying the lines, "Dammit, Jim, I'm a doctor, not a physicist!"