You can lose parts of the image if major correction is required,and therefore the ability to compose precisely... and indeed the whole point in having a 100% viewfinder - although barrel distortion is less prone to this, excessive amounts will mean you lose the corners upon correction. Surely it's better choose a lens with less distortion though, even if it is fully correctable?
How close were you to the shelf??
Fairly close by the look of it... which isn't helping.
Looking again at the images, it's obvious he's closer to the shelf with shorter lengths... which is really a bad idea, as what appears to be barrel distortion may well be made a lot worse by the shelf being so close.
Not a great test image really. These images are not really selling the lens very well. I've used this lens myself, and don't recall it looking so horrible at the short end.
Vignetting looks pretty bad wide open too. I know this can be corrected too... but effectively, you're correcting areas of the frame that appear to be around 2 stops darker than the rest. You're recovering under-exposure in those areas, and that always reduces quality, especially in the shadows. Recovering shadow detail from -2 stops WILL increase noise. Fact. I don't recall the one I used being that bad... then again, I never used it to shoot a single colour wall.
Something strikes me as odd here the more I look at these images. I don't recall the one I used being as bad as this. We talking about the same lens here? The AF 24-70mm f/2.8 SP Di USD VC
Overall this is a great lens... I just don't think these images are doing it any favours.
One thing I did notice with this lens though, is it's nowhere near as good in the middle of the range for sharpness as it is at either end. 40-50mm were quite soft unless you stopped down to around 5.6, and even then it wasn't stellar. For the price though.. still a good lens. All mid range zooms have their respective poor points regardless of price.
This is still a lens I'd recommend as an alternative to the Nikkor 24-70, simply because it's so much cheaper.