Half-swording is ONLY good with the German and Greatsword, but only situationally.
In those cases, you get an ultra-powerful stab to back-stab or surprise enemies with.
With all the other swords, the cut damage is too weak and the thrust not strong enough to be worth it.
I do not agree with the current situation in half-swording.
Right now half-swording gives -1 speed, less reach, very shitty cut on most swords, but good thrust...basically never worth it.
To fix half-swording, make it so speed is not decreased by -1.
Also, give +2 cut damage compared to what it is currently.
That way, using the weapon as a 2h gives better reach and still much better cut damage.
Half-swording decreases reach, gives better thrust, and less cut.
The changes suggested here would not make it OP, but would make it somewhat more viable than it is now.
Do it!