Generally Axe Spec > Sword Spec always.
However, the item level increase almost always trumps the weapon specs. My gut is telling me to go with the Claymore.
But you need to confirm that for yourself:
1) Go to a test dummy and run some test on your dps.
2) Use a spreadsheet to math it out.
3) You also have to try and figure out if the weapon dps is more important than the increased ArP for you in arenas.
Sorry I don't have better answers (I don't arena any more) but hopefully that can get you moving in the right direction.
"A man can learn twice as much from milking a cat as two men can from a very tall fourth man.
- Mark "Alec Baldwin" Twain