You are guessing wrong on all counts. First of all -- of course I've shot it. While it is new as of this past June, I've put several hundred rounds of birdshot through it and recently switched over to buckshot, having decided it is broken in enough. As for the stud -- not just my opinion, but that of several others whose opinion I value. A weak link in an otherwise great gun. As for collecting dust -- where did I say that? Did I not say it would be used at the range? As I am retired, I go to the range often.
From the original post is just seemed like you bought it for HD and didn't plan on using it much, so I apologize. I'm sure you can imagine that I've (and many others) have run across many folks who buy a gun and never fire it... literally never. Glad to hear she's seen good use since you've bought her!
That said, I still don't think the original sling swivel is a weak point of the 590. I have run thousands of rounds through my 590A1, most of which with a sling attached to the original mounting location. I just haven't seen the evidence to the contrary. But... to each his own.
On that note I would still suggest the Elzetta light mount. I believe as an upgrade option they make a QD swivel option that attaches directly to the flashlight mount.
http://www.elzetta.com/zsm.html and http://www.elzetta.com/zss8700.html