One of the things I've been thinking about, with regards to Stewie, is her size and build. Compare her to DT, to Maya, even to KML (who is getting open looks even though not letting that happen is defensive priority 1B after denying Stewie). They all get physically harassed by the defense. DT had the crap beaten out of her during her senior year and still outplayed them all.
And they are, all four of them that I've mentioned, more or less in the same weight class*. Stewie is four inches taller, and longer, and leaner. Her build doesn't pack on muscle in the same way. I've been thinking for several games now that the very physical defense is more disruptive to her than to our past superstars because her build is not suited to absorbing it. DT and Maya, in my opinion, have builds that are just a hair bigger and more muscle-y than a classic athletic frame. The extra bulk helped keep them from getting pushed around. Stewie is longer than almost everybody, but pound-for-pound she's not that powerful.
*UConn doesn't publish weight, but official WNBA stats show only 25 pounds between DT and Delle Donne, and I don't think Stewie is bigger than EDD. DT may have also gotten leaner since college, but that's hard to judge because the uniforms are cut differently.