(Commenting based on Legend difficulty. I feel that the Greatsword is less viable on Legend, compared to Cata.)
I pretty much only use the Greatsword on GK, where it can be paired with a high single target damage weapon. I think your suggestion is good since that will make the GS a more viable choice for the other careers. With the GS, you’re pretty much forced to repeat push attacks and drain your stamina quickly if you want to do optimal single-target damage. This is especially annoying on Foot Knight since pushing or push-attacking enemies knocked to the ground will make them immediately stand up.
There was a similar well-received feedback post in Reddit /r/Vermintide:
https://www.reddit.com/r/Vermintide/comments/u31nyb/a_simple_buff_for_greatsword_2h_sword/
Add a light attack combo that comes only after push-attack. It should be a repeating combo of overheads that has the exact same properties of the push-attack. You cannot combo into the normal light attacks from this combo, only the heavy attacks.
Variant 2: Instead of repeating overheads, you grab the greatsword in a half-swording stance and do repeating thrust combos, which in turn would make the combo:
Push-Attack → Half-Sword Thrust from above (L3) → Half-Sword Thrust from below (L4) → repeat L3
In Variant 2, the damage would still be the same, the animation and hitbox work would be different.
You get some extra nuance of the greatsword.
You solve the issue of burning stamina, spamming push-attacks for average anti-armor hits. If you are really crafty with dodging, you can keep an onslaught of anti-armor hits on something like stormvermin packs: by the time you need to block or push-attack again, you’ll have your stamina back.
[…]
OP meant Kruber’s Greatsword (Two-Handed Sword), not Kerillian’s Dual Swords, whose push attacks can go through shields. Greatsword push attack does not go through shields.