Something I have been thinking about recently has been how could other weaponry, clothing and items be added into the game without it breaking the feel of the authenticity of the experience.
A museum! A large complex type building that is set up like a special location, similar to the shipwreck at Riffy.
This would be the only location to possibly find say the AUG, or even the M4 but maybe even weapons that are more period than this too. Muskets? M1 Gerand? Swords etc? WW1 and 2 era weapons from all sides, the Japanese Arisaka?
This could push beyond just weaponry; Clothing and items could include some WW2 themed uniforms, backpacks? Just an idea I had, so I threw it out here.
I think some more special locations such as the shipwreck would really add to the game. Possibly have the museum far West? Maybe on Skalisty Island?