Would have been better without humans
If the humans had been kept in suspended animation on the ship, instead of being obese people who spent way too much time online instead of being aware of what happened around them, it would in my opinion have improved the movie.
Then again, Pixar seems to feel obligated to teach the audience something "important" about life, and used this as an opportunity to say something about our society. These boring messages are one of the reasons why I don't like Pixar as much as so many others.
Still, Wall-E is by far my favorite Pixar movie. The only thing stopping it from being perfect is as mentioned the humans (and I don't know why they used live action footage in the movie). Instead of being introduced once Wall-E enters the ship, it would have been better if they did not show up a short time before the end of the movie.