As an avid OFP player, I would ask the developers to forget the idea of doing Vietnam...
The plot for "Independence Lost" seems much better. Or perhaps a US vs. North Korea based in 2005 or so... Perhaps Israel vs. Syria? Germany & France vs. US & UK? heh-heh...
There are PLENTY of scenarios that would be a lot more fun than Vietnam...
I think it would be a mistake to go back too far into the past. 1985 was ok, but 1965? No way... I for one like the new weapon systems. I'd like to see more use of artillery and UAV's...
Whatever they do though, you know I'm gonna buy it...