Agreed, until then, I thought that brush was almost useless... I actually find that bluring out the pixels works way better. I've been using it on some vector practice of mine, however, those are solid colors so that might be why it would work better. If you use the blur tool though, and magnify the image so you can work clearly, it might help. Out of curiosity, what did you do in the tut?
I'm going to be honest, the displacement technique is awful. It ruins any flow you might've mustered up from the depths of Loch Ness, throwing it under a bus. Bottom left of her head, there is some displacement. It is a different color, and should've been erased. Displacement only works sparingly, to add some depth. Here, there, and it's good. Like a small clipping mask. Displacing around the entire focus does not do anything for the composition, it actually degrades from the focus, and I assume your attempts with displacement are to focus in. I start eying the displacement, instead of the focus, wondering, "Why is it around the hole outside?" and I continue to look at the background, the focus is attention deprived.
I would have smudged and all that, but I wanted to give them an outcome from their tut. I will do that, if I do the tutorial again.