Hello. While this had been recently suggested, it was voiced merely as a thing that would be nice to seen in the mod, and now I'm voicing a "normal" suggestion. I talking about additional one handed modes (togglable by pushing "x" button, when shieldless) for both bastard swords, katana (not sured about longsword, since it's best application is half-swording), perhaps some other similar weapons, if they 'll be added to the mode. Balancing might require some penalties, but hopefully lower, than when these weapons are used with a shield or on horseback.
Additionally, it would be nice to have a togglable two-handed mode for some of longer one handers (long arming swords, etc.) to be added, perhaps with some minor benefits, like +2 or 3 cut and pierce damage.
As far as I remember, shorter bastard weaponry was more often used as one-handed, and katana is specificly adviced (at least, according to the translation I own) to be wielded one handed by Musashi Miyamoto himself.