I honestly liked the movie. Even if Tom Cruise added nothing, there were forced subplots about kids wanting to run off to war that never got followed, etc. (And Mr. Cruise, I don't care what you think you know about psychology, science, or the gaping hole in your ass -- shut up and dance for us on the screen like the monkey puppet you're paid to be, alright?)
But overall I did like the movie. Decent job, most definitely.
However, my biggest criticism of the movie plot variation from the book/previous 1952 movie. If we presume:
1. these aliens are from a technologically advanced civilization (enough to master mass destruction and space travel)
2. said aliens had planned this invasion for eons by planting their warships under the earth's crust before the advent of man
3. we feeble earthlings in our technologically inferior society have a rate of technical change/innovation where we cannot bear to use a computer for more than four years before it is useless landfill
then what the hell are these aliens doing, having to attack the earth with warcraft that employ million-plus year old technology?
Could you imagine being one of these aliens, having to be deployed to earth? All your friends in the military back on planet Zeldar are zipping around with interstellar hyperspeed ships with universe destruction bombs. And you? They are laughing at you hysterically for getting stuck with having to attack earthlings while riding around in what is essentially perceived as a wooden oxcart with a cork gun.