See, Crysis 1's Levels are big, yes, but they are not full sandbox and open-world. THEY ARE corridores, but large. I can think of several: First Chapter - beginning, Second Chapter - beginning, ending, Third Chapter - beginning, and all the rest after Core. They are large corridores. I could have said "Crysis 1 is open space" and mention the "Onslaught" Level, but that is purely the biggest open Space map in that game. So I'd compare it to "Unsafe Haven", wich is the biggest open space map in Crysis 2.
If Crysis 1 would be a full sandbox game, we could explore the whole Lingshan Island in one map. We can't.
Linearity is not bad people. I'd rather take a more linear (but still enough space for free decisions and ways to get through that situation) Crysis with a better presentation, storyline and mindblowing moments, then a ultra free open world Crysis, where the adrenaline meter stays always at the same level.
Proof me otherwise, but don't just spam "You're wrong!" without giving me concrete answers and examples.