I cannot see why the AI should be any problem at all. Making everyone hit the dirt and hide behind objectives can be scripted, and should be scripted for a successful Omaha Beach mission. The biggest problem is the shortage of the fight. Sure, spray can be scripted as well with those two wonderful scripts at the scripting: beta testing forum but the player can just put a Garand shot straight in the MG42 gunners arse and then it would be all over.
There is a mission at ofp.info which is just as my previous suggestion a bloody noob mission. I even had to open it up in the editor just to make it work propely (the boats were crashing in to each other otherwise) but once you get on the beach with 7 other squads along with yours and everyone is dropping dead all over the place. Damn, it's such a good atmopshere.
But of course, it's not a 9/10 as I said and there is no realism (82nd are landing in Higgins boats, err... no) and I don't think there is a single script in the mission.
EDIT: Another problem would be to make it balanced. How the hell can one little player decides the fate on Omaha Beach. Sure, it's fun to play a grunt in something really big but if the end of the mission doesn't depend on the players action... Well, that sucks basicly.
:beat: *Gets Shot* :beat: