Or they could pull "Liquid actually lives" off the cutting room floor as a lynchpin for an alternate universe. That'd have more impact on the timeline, and it'd be bringing back a fan favorite scenery-chewer to balance out the fanboy tears. There's a lot of cut content/abandoned ideas for MGS2 that people would love to see, and 9/11 is a long time ago now.
If anyone's going to make a MGS movie, on the other hand, they need to start with Snake Eater and they need to do it before Werner Herzog gets any older.
He'd be perfect for the job. Herzog knows about the savagery of Nature, the wounds of the Cold War, the tragedy and absurdity of the human condition, that sometimes a man is just made out of hornets, and that sometimes you just have to work in a ton of exposition. Send him out to a temperate rainforest with moldering concrete buildings and assign him two PAs: one to keep track of Metal Gear lore and one who keeps reminding him to make things more horny.