Comics Continuum has an interview with Hugh Jackman which discusses the fan feedback on the first movie that prompted the sequel to feature a more raging Wolverine.
However, in an Entertainment Weekly interview (Entertainment Weekly #709, pg 26), Hugh Jackman claims that Wolverine doesn’t go for mortal wounds even when in a berserker rage in X2. “You’ll notice I never stab people near major arteries or organs,” Jackman points out. “But nonetheless there is certainly a little berserker rage going on.” (Don’t worry, that’s not a spoiler if you’ve seen any ads.)
I’m not a doctor, but I should think all that puncturing around collarbones and ribs would be pretty mortal. (I also don’t get how his claws can lift a person if they are supposed to cut through anything.)