Here’s a link to may initial attempt at animating a realistic looking walk.
Comments and suggestions welcome.
SR
It needs some vertical hip movement. If you watch the head position of someone walking, it goes up and down in a wave-like motion.
Beyond that, i think it looks good indeed 
I agree with fjordhoj’s statement. To add on to what they said, there’s a lack of movement at the ball of the feet to help implicate
the squash and stretch rule. Turn the heel up every time the back leg is pushing the body forward.
Whoops, got a double post out of editing.
Both of you have identified two issues I struggled with on this. At first I had a significantly longer stride which resulted in more natural vertical movement, although it was so much that she ended up looking like a marching soldier rather than a strolling girl. So, I reduced the stride to make the gait look more relaxed and less forced. That resulted in a difficult situation where because I am attempting to model a cat walk which is a rather unnatural gait to begin with the up and down peaks occurred rather close together after I compensated for the significantly stiff legged cat walk style, and that timing added a kind of lilt to the walk that was unintended and divergent from the cat walk was I was trying to capture. So, I reduced the upward motion at the peak to hide that odd vertical timing that it ended up having.
I did use some walk cycle images for reference that included the one mentioned, although I also watched and analyzed a number of fashion show runway videos and found that the troughs and peaks of the walk shown in the image are timed differently than where the troughs and peaks occur naturally in a models cat walk. So instead of forcing the timing in the image on my animation I went with trying to capture what I saw in the videos.
Also, I noticed the lack of realistic heal rise in the process. I did take time to add in somewhat more than was first present in the animation. Although I had trouble doing that without throwing other things off. I found adjusting the angles of the foot to match a realistic heel lift and toe rises to be quite challenging, and I would like a clean side view video of that for a reference. In the videos on YouTube there are lots of front and back views of models walking although I had trouble finding any clean straight on side views. I found some passing 1/4 and 3/4 views although an absence of any that tracked spot on sideways for a few good steps. I’m wanting to make some myself for that.
Thanks,
SR
Oh, very good, thanks.
Maybe, I’ll have enough there to make a second version.