not much. the expertise bonus is nice, but really only plays a big role at the end game. of course, if you *can* use swords/maces, then by all means please do. but if an axe comes along thats just plain better (better damage, stats etc.) then go ahead and use the axe. dont let you racial keep you from using a nice upgraded weapon.
I say dont sweat the weapon axe or sword till 70 and beyond. Expertise is a hell of a stat! All about aggro and you will love seeing that dodges and parries from mobs become a rarer and rarer occurance. It would only play a part if you happen across a a sword and an axe with identical stats, which one do you take? As a human you better grab the sword, as an orc you better grab the axe, but when the hell does that happen?