I think that a demo is necessary to get the word out about Crysis 3, just as it did for Crysis 1. Its got loads of negative attention right now!

Especially since:
More people pirate games when there is no demo. A "demo" and not some beta actually helps to reduce piracy by allowing people to try out the game early for free before paying with their hard earned cash for it.

The demo for Crysis 1 did get a lot of attention, when i checked ea games, and I'm suspected it should have been the same for the sequel Crysis 2.

Because reviews and videos will not prove anything without first hand experience.

I don't share this opinion but if people get the idea that there's not enough to set this game apart from others and a potential customer reads a review that says "GREAT GAME but it's just like xyz", that's one less copy sold. Since Crysis 3 is pretty much sure to become quality entertainment you cannot go wrong with a demo and personally, when I see a new demo on Marketplace I immediately like the developer and franchise more just for being transparent, for putting their product out there for me to test before I buy it.

A demo is a must. I need to see if I'm able to run the game smoothly! Many people pirate the game just too see if they can run it!
And of course, there is the gameplay we need to see