I agree, but I think it's a mix & match situation. With basketball moving towards the taller, more athletic wings, the vintage Power Forward that would potentially over-match Williams might not be seen as often. I'd rather have my "3" be able to over-power his defender and take him to the hole, with the option to dish to my stretch-4 - Williams - in the corner.
Let's take Buffalo's roster for example (from last season). Perkins at the 5, Harris/McRae at the 4, Graves at the 3, and then Caruthers & Massinburg at the guard positions. Williams could very much handle a Harris/McRae matchup, and that would leave Reece with a pretty big mismatch against Graves - in favor of Reece.