I had to hardwire my (also) Samsung BR player to my router to stop the hiccups. I tried everything, but using the wireless, Netflix choked from time to time.
I started out with the WiFi dongle and then did the same thing as you—went wired. Not sure whether it helped or not.
Often when a Netflix program is unplayable I log the problem at the Netflix site. When I try a day or so later, it seems to play OK. Could be just coincidence, of course.
I wonder whether some of their programs are held on servers that get overloaded, or are on WAN trunks that get overloaded. I’m sure they have one helluva server farm...probably more than one—with about a 6 inch diameter fiber to the backbone. ;^)