If you have same amount of vignetting at 4 corners @ 24mm to 30ish, then yes...it's normal for the new 24-70 f2.8 II. I tried 2 copies and both have similar vignetting at that range. You should be able to fix that vig. in LR with just 1 click
What about sharpness?
I have one..it vignettes pretty severely at the wide end...at first I thought it was the normal-depth B&W filter that I put on the lens..as it was just at the very edges...have been meaning to find a white wall to test it, with and without the filter @ 24mm.
My copy seems very sharp...I did test that against my Sigma 50mm @ 2.8 & 8.0 and I would say that the two lenses are equal in sharpness. amazing for a zoom...so I am not throwing it out ( although the price tag still hurts).
I will try to test it out at the wide end with and with out the filter and get back to you here. I am curious, too!