I really like the feeling of chuckin' spears at my enemies. Anything to boost its viability as the ages progress would be cool with me. I am surprised we can't produce a better spear outside of raw damage values. It's weird we've got this bowstave that's only used for longbows, so you'd think we'd be able to craft a similar staff for spears, providing at least an accuracy bonus that is currently lacking in the standard metal spears. Could call them "Javelins" to avoid confusion.
But I worry that might be tangential to the core suggestion here, which isn't about making spears more viable in the late game, but being able to carry a lot more of them in the early game, no?