The SEZ policy like most other policies is a mess because of the politician-corporate-land mafia nexus. Politicians have cornered land using the mafia and now are waiting to palm it of to the highest bidders using the SEZ act. Corporates of course have no problems buying from these cartels since they don't have to do the dirty work. Of course they would prefer the govt's stamp on it!
Also it is often mentioned that "it will be difficult for the govt. to do this or that till elections are over". But then how is it that the govt. is willing to do that "something" after being elected, and which is not possible when elections are down the corner. It shows how the so called "elected reps" work for their selfish interests once they get elected to office.