From what myself and @clever aspen saw, the lockers should be penetrable by medium pen weapons also, as long as they are shot head-on, avoiding the sides of each individual lockers. Back-to-back lockers are unpenetrable though. I can't be certain this is true until I actually go test it in-game though.
I do generally agree though that there is too much stuff that blocks wallbangs for medium pen weapons.
However, I think the primary issue with Killhouses is that they gen with too many rooms, and a lot of those rooms are very ratty and difficult to clear properly with flashes.


