My last two CE's I've received from a local retailer haven't been as perfect as I had hoped. Sonic Generations had a small dent in the lower right hand front corner with the outer plastic being crumpled slightly. My MW3HE had a small mark on the centre bottom edge. Not as much damage as you received Twisted, but very annoying nonetheless.
I emailed the shop and they could only offer me a refund.
The damage wasn't severe enough to warrant this and I much rather keep them, considering it's next to impossible to get replacements, without paying a highly inflated price.
Having said that, whenever I pre-order games from a bricks & mortar store, the 'damage' seems to be worse overall than if I order online. The store clerks don't handle the bigger CE's with much due care.