There should be an "I don't really care" button... I voted no, but not because of Welling himself, but because of the universe created by Smallville... The show was ok, and Welling was fine, but I just think Superman of the movies should be more in line with the established comic book storyline, or that of the original movies... I don't mind a reboot, THAT much, as it's been many years since there was an "origin" movie.
Routh's movie was a loose continuation.. Well, maybe not THAT loose, but it tried to stay true to the spirit and intent of the Reeve movies. Routh was not a clone of Reeve, his character was. I think he was great in the roll and would have liked to see him back.
I think Welling or hell, even Cain should have had a shot at testing for the roll if they had wanted it, just like any other actor could have. But Caville is what's happening now, so so be it.