I was also kind of fond of the movie...
(stands his ground)
It didn't have quite the same low budget charm of the original, but it wasn't that bad. In particular, I liked how Gary Oldman turned Dr. Smith from a bumbling fool into a fairly serious threat.
Now, back to the original show, Dr. Smith being a bumbling fool was one of the primary plot drivers. True, like Gilligan, everybody's life might have been a bit easier if they just shot him, but they would have lost a great character. Jonathan Harris did a wonderful job making Smith an over the top coward, more interested in self preservation than in teamwork. But he also did have some redeeming qualities. The interaction with the robot is classic duo comedy and we did get to see that he actually cared about Will. Smith even gets a few moments of heroics.
Nope, I'll hold the middle ground here and say that both are perfectly valid interpretations of the story.
Just don't get me started on Battlestar Galactica....