While for me 1/35 and under are great for accompanying armour and populating dioramas etc, large scale figures rock for portraying a specific character!
I like your idea of the 'Full Metal Jacket' character, which could be expanded upon with several of the characters, somewhat akin to Bravo6's Platoon figures? The figures would be popular as a collection, for a large scale figure dio and individually as standard Nam figures.
A club-mate has ordered 2 of the Alpine 1/16 USMC Sniper, one for himself and one for myself, so looking forward to that. Will convert mine to Modern Irish SOF in Chad, and most likely will buy another down the line to build and paint in the original USMC form.
While I mention that, I would like to see a company do a series of 1/16 or larger figures in a series of Modern European Soldiers as you would see in Afghanistan, Iraq, Africa, and other Middle East missions. Of course I'm biased and would love to see a figure of an Irish Soldier in the new body armour, assault vest, STEYR with grenade launcher and laser designator etc. Though most likely I will have to sculpt these myself in the end.
Of course in line with this I would love to see really high quality large scale modern German, Spanish, Italian, Polish, Czech and French though some French are out there I think? I also think modern Chinese PLA figures would prove popular, there has to be a big home market there waiting to be fulfilled? I always fancied the idea of doing a 1/16 North Korean and South Korean facing off across the border!
What would really be great though is a WW2 German in generic SS/Wehrmacht uniform, looking into the distance, and do I dare hope maybe pointing?
Looking forward to seeing what ideas come of this thread!