I realize that lists like these are somewhat subjective, and I'll first say that I have not yet had the opportunity to see most of the players on this list.
But I have seen Elizabeth Balogun play 15 games for Louisville and if there's a better wing defender in WBB this season I've yet to see her. In those 15 games Balogun has 18 steals and 27 blocked shots.
I looked at the stats of two non-bigs whom I have seen play a couple times each. Chasity Patterson in 15 games has 60 steals (amazing!) and one blocked shot. DiDi Richards in 12 games has 20 steals and seven blocks.
Balogun's blocks compare favorably with those of Cunane (14 in 10 games) and Nelson-Ododa (20 in 10 games). Boston is way up there with 41 blocks in 13 games.
Every fan has a bit (or more) of homer in him/her, but in this case I really feel that Balogun has been overlooked. I'm not saying that she is the best defender in WBB but she has to be in the top 15.