I didn't do nearly the kind of research I did in the last few years, but I'm not pressed by the pick (as the kids would say).
The upset crowd comes from him being selected at #28 with a 2nd round grade? I mean... okay? Does that mean that if the Lions had selected him at pick #35-40, a pick they don't have, it would have been fine? It takes two to tango with trading, and there really wasn't a lot on the board worth jumping Washington, Buffalo, KC, and Philadelphia for. It's like the Jack Campbell pick - just because you think he would be there 10-15 picks later doesn't mean he would actually be there. You like him, he's there for the taking, don't overthink it.
I'm guessing he didn't have a 1st round grade from Holmes either, but you can't expect Holmes to jump 10 spots every draft to get the last guy who's falling that meets that criteria. Williams was the best player on their board, and if he is in fact an Alim McNeill who is getting a nine-figure extension in a couple years, he will be well worth the 28th pick.