I was really scratching my head over my previously posted capture - no matter what I did I simply could not nail it and the arm just looked utterly wrong. I am ashamed to admit how long it took me to spot the mistake, and rest assured my face glowed like the setting sun once I'd clocked it.
I had the arm swinging with the wrong leg. I got it backwards. Amateur mistake.
As soon as I'd finished bashing my head against the wall for not spotting it sooner, I flipped it to the other side and it instantly looked a billion times better:
More to the point, it was much easier to "read" for mistakes. It's still very much a work in progress, but simply fixing that arm has made one hell of a difference.
What followed was a series of tedious and very samey captures that I can't really talk much about aside from saying "the arm is too far forward," or "his shoulder pops here." I don't know, maybe that's valuable, but I talk too much as it is. I find it much easier to reflect/critique this stuff when there're more changes, so I'm just going to jump ahead a few versions.
Lots of minor tweaks to the position of the arm here. The biggest change in this version is the shoulder - I wiped all previous keyframes and approached it in a much more straightforward manner. Before, I keyframed almost every aspect of it by hand which led to a slew of inconsistencies in speed and spacing that I believe may have contributed to some of the random limb popping and slight jerkiness in the previous versions. All I did this time is slap a couple of keyframes at the furthest points of its swing, then added a one to the first contact pose to have it move in a slightly smaller increment before it swung forward, giving it a little delay. I think it looks much, much better now, and the arc of the arm is clearly visible.
I think it's safe to say that the blocking of the arm is done at this stage. It's still not perfect, of course, but I think I'm ready to add in the opposing arm swing and also start looking at fine-tuning the timings and getting some wrist movement in there. The head is too static, too, so I'd like to get a bit of follow through going on that. I may also return to the legs a bit later as well and see if I can do anything to improve those.