Think the OP is using a microscope on this issue, and that I think these 2 swords are close to perfectly balanced.
On another note, I think the weapons are too similar. The stats for them should be shifted around a bit to make them more distinct.
Take some speed from the heavy bastard, and translate it into cut.
Take some cut from the longsword and put it to thrust.
At least then we'll have something like the mini-versions of DGS and GGS.
Make them more different from each other.
Oh and just to compare the katana to longsword once again:
Longsword
weapon length: 106 +11
weight: 1.8 +0.5
difficulty: 10 1 more req
speed rating: 98 -3
thrust damage: 23 pierce +7
swing damage: 36 cut -1
slots: 2
Secondary Mode +
6,660 -2716
Katana
weapon length: 95
weight: 1.3
difficulty: 9
speed rating: 101
weapon length: 95
thrust damage: 16 pierce
swing damage: 37 cut
slots: 2
9376