I do like that idea but how about have 2 classes of spears. One is melee use, longer hit reach, higher damage, power attack would be a big thrust that would guarantee a knock down if hit at cost of huge amount of stamina, half stamina loss if misses.
Throwing javelins, you would have something like a quiver of some sort, have a stack of 3 or with mods 5, Give it zoom like the bow does. For mods for it, large bag, allows 2 additional Jav's to be thrown, not sure what to call it but a mod to allow quicker reload speed, grabbing the next jav quicker, sturdier shafts, allows higher chance of recovering jav's from bodies or hard surface cause they have a high chance of breaking. Pretty much treat them like arrows but make the materials more expensive then what arrows make.
I am a huge fan of the spear but it falls off so fast once I get a hold of pipe weapons. One thing I do use them for is for stealth attacks. They are silent like a bow, they are nice so when you are low on ammo. But they are obsolete the first few minutes of game play and is forgotten. If they don't get a update then what's the point in having a useless weapon that no one will ever use on horde nights. Would love thought to have a spear as a main weapon like a club or 2H hammer.