I liked Green Lantern in places. Didn't love it - it has serious flaws. But I don't think it's the POS that some people do.
Still, here's what I would have changed in order to improve the film :
- Overcoming 'fear' was a very obvious story arc, but they really, really overstated it at times. Fear, fear, fear, fear, fear, fear. The audience isn't that stupid. Tone it down a bit.
- Hal's constant self-doubt and 'quitting' being a GL. Overstated again. And he didn't really 'quit' anyway, he just didn't put on the ring at
that time. Stronger characterisation and consistency is needed - he's cocky and confident most of the time, so it didn't make sense that he suddenly became a quitter.
- Get rid of Hector Hammond. I don't think he added anything at all to the storyline other than serve as filler until Parallax arrived. He could have been saved for a sequel (or use Hammond, and save Parallax for a sequel) with his powers explored a bit more
- Improve the writing. Some of the dialogue was just plain sloppy. "I know, Right?!" has become an internet meme for crying out loud.
- Most of the actors were well cast, but I thought Tim Robbins was woefully miscast as Hammond's father. Asides from the grey hair, the two look about the same age.
- CGi needed some improvement. It just looked too cartoonish in places. Whoever is doing the Hulk in The Avengers should be given lots of $$$ and told to take good care of GL
- Parallax should have been personified more. I would have thought after seeing Galactus and Darkseid reduced to 'big nasty, dark cloud' form in other medium, filmmakers would have learnt that an evil cloud chasing our hero is not really exciting, interesting or scary.
- More epic space travel/battle needed. The final battle went from Earth to Sun in seconds, as stated above. Virtually nothing but empty space in between. Why not have a chase through one of Saturn's rings? Or a battle on one of Mars' moons? They could have made it much more varied and exciting.
There's more, but I can't think of it right now.