The main reason this game would not be the same on a console is the "physics" .The physic's in this game are like nothing we have seen yet,then you add the size of the world which requires no zoning/loading and the DX-10 technology.But mostly it's the AI and the Physics that will make it near impossible to replicate,although a dumbed down version would be possible considering it is also DX-9 compatible.
Yes there are games like Gears Of War that look great, but you cant compare the two. Gears of War has your typical single player maps where you are basically playing in a box, you cant climb the mountain in the background and physics aren't even close to Crysis.In Crysis you can walk to practically anywhere you can see the map is huge.
Here are a few video's, these are pre alpha.
http://files.filefront.com/Crysis_Multiplayer_DX9_Movie/;7479657;/fileinfo.html
http://news.filefront.com/new-crysis-zero-gravity-video/
http://www.crysis-online.com/Media/Images/Screenshots/Village-01.jpg
after seeing this video there is no way 360 or PS3 could run this.
http://www.gametrailers.com/player/usermovies/62449.html
This is just a hint of the future of DX10 , Crytek has stated that they took it easy with Crysis to make it compatible with DX-9 and today's PC's. They have stated that there next project is "DX-10 only" and is a whole level above Crysis.