Ah yes, the old Amiga... I finally threw my Amiga 100 away last month after keeping it all these years. That was very hard to do <img src="/ubbthreads/images/graemlins/disagree.gif" alt="" />
OK, let's talk basics here: You are the Hero, you have an involuntary appendage attacked to you (the DK). Don't forget that you are the Hero, and you should build your strength there. The DK should be used for your support in the manner you feel will be best. If you look at the DK as your main strength, and your Hero as the support character, then you will be sorry as the game progresses.
Why 2-H over 1-H? Quite simply it is for the added damage. Many times it will be imperative that you take down several enemies as quickly as possible (my 2-H damage is 259-385). Granted the Shield Blocking may have some advantage, I have not played that skill yet. But I can tell you that in my first game (Tactical difficulty) I had enormous problems in the final battle with 1-H and Shield. Once I switched to 2-H in that battle I could handle the big guy (bearly, but after killing him several times I have his number now).
Remember that in some situations if you do not take the enemies down quickly you will take massive melee and magic damage from hordes that will attack you You will understand better when you meet Earth Elementals or Clerics).
Most people like to play a game the first time as a Melee character, then try other combos later. I can assure you that in this game a Melee character will have the most difficult final battle of any class, you will just have to wait and judge that for yourself.
I would step up the difficulty level though. If you are playing Very Easy, you might want to go to Action or even Tactical if you are an experienced gamer.
Hope that helps.