I've been looking at this for ages now trying to figure out why it's not working for me... it's to do with the amount of frames you're dedicating to the grounded foot...To me it looks like the grounded feet are on the floor for 1 frame too many and inversley the swinging forward foot isn't in the air along enough... it snaps back to the start quite awkwardly.
Perhaps you may want to revise how long each foot remains planted for? I think if you reduce the length by 1 frame (not physically drop frames) then use that to increase the air time by 1?
It's tricky to tell but there's something not quite right there?
I've done a really quick hacky edit on that front leg to try and illustrate this...
now I've looked closely at it, you've got an issue with the arm swing in relation to the legs...
you've got the arms swinging in a nice 4 frame forward 4 frame back... but the legs are on the ground for 5 and in the air for 3... which is causing a visual clash around the point the arms are at their most extreme... it's really tricky to describe, but visually it's creating a weird sense of time displacement... it's like the arms are 1 step ahead of the legs and then they synch up again only to go out of synch...
on a positive note, the shapes are nice and you've got a good feel of mass but you need to address that weird out of synch thing...
I hope that helps?