Even as one of the most prominent stab (ab)users, I say that in the current state of the mod the thruststun must exist. The stab is a wonky attack, and since it can be so heavily twitched in so many ways there needs to be a downside to it or stabs will be OP.
Especially with the current sideswings, the thruststun is basically the only reason I use any other attack than the stab.
That said, if they would speed things up (not necessarily through gamespeed, but through weapon stats and whatever) I could see a reason for the removal.
If it's possible though, maybe reduce the effect of stab-on-shield imho, but then I'm pretty biased