Most spears are not designed to be used like that and would mess the spear head up after a few blows. You need to design the weapon for that purpose or the pin or compression fit spear heads will just come off. I would just keep the kung-fu swings to certain polearms like glaives and sword staff type weapons.
The good news is there are a few spears in game that you can swing like the menavliation that you can buy in the empire settlements.
I don't know that I agree with that however thrusting is the most effective way to use a traditional spear. The problem with this game and spears is that weapon damage seems to be based off of velocity and spear thrusts don't have the velocity of a weapon being swung. This then leads to another problem, spears need room to be used. Often to use a spear effectively, you have to back off to give yourself room, which the game unfortunately translates as negative velocity which in turn means you do even less damage with your thrust.
What really needs to happen is for spears to be decoupled from the velocity mechanic in some way, form or fashion and then have its base thrust damage increase significantly so that your basic thrust has nearly the same damage as if you were swinging a sword. Additionally you should be able to do this damage or at least nearly this amount of damage even if your backing up.