Before someone shoots this down, hear me out first.
A single weapon can be either dual wielded or wielded with a grip for effectiveness.
However, the h2h weapons cannot have a sub weapon for any use whatsoever.
I'm not boasting for double the effects as that might be a bit too much in itself, but suggesting something along the lines of 1/3 more than what would be considered on a single weapon.
There have already been suggestions of perhaps wraps or so, as a sub weapon for h2h users but that request appears to have fallen silent.
It's just something to think about since it seems that only the h2h weapons would be the only weapons that don't have anything beneficial to them in terms of equality to dual wield/grips.