One thing is perhaps to make (at least larger weapons like longswords) have the option of single or dual hand, and for realisms sake, as well as to help this system, you would not be able to dual wield 2 longswords, only a longsword and a smaller weapon or spell. This way, the 2-hand approach, which would also be faster/stronger would have a different yet equal advantage to single wielding, and which you preffered to use would depend on what kind of enemy you were fighting.
Another thing for both HTH and the 2 weapon skills would be to make it easier to get disarmed so that you may need to change weapons during a battle and recover your first one later (though this may cause trouble with not being able to find weapons, I'm not sure). This way, you might lose your claymore and have to pull out a shortsword or vice versa.
For hand to hand, I'm not sure how to do it with the button layout (this is just a basic idea) but make it work with or without weapons, and have more options than before. When fighting, if you have wristguards, they should be able to be used to help block or something, being more effective than the sword if you have sufficent HTH. Also, kicking could be added so that you can stagger your enemies with it in battle.
Just a few thoughts. I would like to hear yours.