See, again...sequels shouldn't be made to 'correct' things...they should be made to continue something really good. Either a really good film, or a big money-maker, or both.
And I really can't see it being cheaper if they're naturally going to want to up the ante with the space/Oa stuff...of which they had so little in an already-costly $200M first film.
Of course, if they really can take the "I believe in GL as a whole", or a best two-out-of-three...then yeah, a sequel's possible. But if it's going to be bigger and better, they've got to find it in themselves to open up the checkbooks again...which is what's probably making a sequel the hardest sell, in light of the first GL. I mean, if you're asking to get more for less, and also make up for the first misstep....might as well drop the politeness and ask people to work for free while they're at it.
But yeah, if there's going to be a sequel, then they've got to show faith with their wallets...instead of pulling funds away and asking for more with arms crossed.