Now I may be biased because I like to use pole arms, but you can still stab with 2handers too...
Currently overhead, left, right parrying makes a lot of sense because the animation shows a connect with the other players weapons and a nice block happens that seems realistic.
But parrying thrust mode seems like you might be holding out a shield which seems to hold a screen from head to toe of the player model. You can just hold parry thrust out and two persons could stab your head and feet simultaneously and you would block them both at the same instant. Also, it doesn't make sense that you can block a stab to your foot as the human arm does not reach that far down. Now I wouldn't see a problem chambering a thrust to the foot, but simply holding out your weapon parallel to the ground would be impossible to block a thrust to the foot.
Now it would be ridiculous to add multiple modes of parrying thrusts (like mouse click down and then move the direction yet again) so I would suggest maybe make it so that overhead parrying also blocks thrusts from the upper chest on up, and the current thrust parrying covers everything from from the lower chest down.
I think this would be a good compromise as it gives the parrying player the ability to block face thrusts and overhead swings at the same time, but give the thrust player the ability to choose a face stab or stomach stab. It would have animations making much more sense and showing connect of the weapons in a realistic manner.
I don't know if removing the ability to parry thrusts to the foot would be unbalancing so I would leave that alone unless a lot of people think that should be changed. If that was changed I would include the issue with shielders so people try to get around that by attacking their feet.