I have a general critique on weight. It doesn't feel like the sack run cycle and the one where the sack is dropping into the ground (mostly on the second bounce) accelerate quite enough as their mass is coming in contact with the ground. I don't know how much you've been using the graph editor yet, but if you have, the easiest way to make the acceleration more convincing is to grab your tangents on the Translate Y and rotate them up.
From this:

To this:

You can also try offsetting the timing on the body forward by a frame so it starts rising slightly later, having it sink a little slower, etc... but all this is stuff you know.
I don't know if it will be relevant to you, but when I was at SIGGRAPH and showed my work to the Disney guys, they told me I should be thumbnailing every key in 2D before I put it into 3D. This is because, for people like you and me, our 2D is stronger, and we need to work on getting all that essential 2D goodness into our 3D stuff. 2D lends certain strengths to animation, specifically things like cheating space and angles, making good silhouettes, and making nice arcs, squash and stretch. Making a 2D thumbnail of your key pose will help you translate those strengths into 3D.
I've never used hogan. Is he any good?
I really like that monster attack picture!! Brilliant how you used the shadow on the wall to make the old woman seem like the monster and the monster like a helpless baby.
