I think, spears are very powerful the way they are and ballanced only by mantainance, carpentry and rarity of tools, to craft those. And.. Kinda risky to use in tight surroundings.

In pre 41's you could have almost 100% consistent knives one hit kills with knives and such having zero skill in blades. With a bit of practice. I think, the animation is even longer, than with spears and it is done at point blank distance. Nethertheless, people went like looting a crouded school with knives.

The key is kiting, if you have enough space around. Not in a straight line, if there are like two or three at the same distance but with some spacing between them. Use corners, obstacles to split them. Be cautious about surroundings. Space key is for shove, btw. You can use it if too many are close. They don't get up at the same moment most times, so it is a way to split them. A good thing is to go sneak and try to lure two or three swinging your weapon. Swing, come bit closer, swing, get attention, kite backwards a bit to deal with those, who separated without disturbing the rest of the group.