No, they're not going to spend less on a second movie. They'll spend more or they won't make one.
I don't think GL is gonna succeed in the movies on the basis of his ring constructs unless they become a lot more inventive. This is one of those things that worked better in the comics than on screen. What he does is sometimes counterintuitive; someone unfamiliar with GL watching him go through his machinations with the oil tanker, springs and artillery gun is more likely to think he's wasting time than to think "wow, cool."
That's IMAO, of course. People will pay money to see Transformers
movies, so I'm probably not all that much in tune with what mainstream audiences will regard as unutterably stupid and what they won't.
I also think Hal ought to lose the mask. They could generally rethink the costuming a bit.