Single and two-handed wielding

[ç i p h é r]

Yes, I believe it would be fairly easy to add in the 1/2 str modifier to any weapon of medium size or larger, if nothing is equipped in the off hand. However, that doesn't address the weapon proficiency issue with the Bastard Sword to use with one hand.

On that front, another possibility might be to make the bastard sword a single handed weapon by default which only requires martial proficiency to use (assuming it's just a matter of adjusting 2da entries) but does not allow another item equipped in the off hand unless the exotic proficiency has been taken. That would simply add some overhead to the OnEquip event and works in tandem with the 1/2 str damage adjustment logic above.