Agreed...they are almost a waste. The EF weapons more so since theres only 1 map which they really feature in, and thats Great Wall.
Supposing EA/DICE did make them available as unlocks, you'd be faced with a few problems:
EF guns would be available to most classes (the L96 and P90 are already SF unlocks). So you would need 2 new weapons to suit those classes.
SF, you would be missing the sniper, medic, engineer, support and AT (well, unless they allow an RPG instead of the SRAW).
The only additional weapons in it, are for spec ops (G36K) and assault (Scar-H). And an RPG for AT.
So you would need EA to create a lot more new additional weapons just to fill the gaps.
Dont get me wrong, I would love to see the FAMAS and the HK53A3 available in vanilla/SF/AF...but it aint gona happen since it will involve more work for those lazy fucks.