your art still suffers from too short legs. it looks really unelegant if the head + torso together are longer than the legs if you have nicely detailled characters (with feet, real hands etc. that they give a feel of believability.) With real chibis, which consist just out of the head and have all other body forms stylized heavily it looks ok.
Posing characters is storytelling!You don't use striking action lines. hat S-rhythm with the forward bend legs and backwards bend upper spine makes your figures look hesitant. If you use that for an armed character it tells a story like "hey I am weak and afraid, please don't harm me" which is absolutely ok if you go for such a character, but generally I suppose you want a bit of heroism.
For that consider the mass center of the body. Usually you want to avoid strict standing poses, unless it's cool posing and you also want to avoid extreme dynamical action poses (unless you are doing the keyframes for an animation) - this means you are left with the
"about to" pose.
The about to pose is the pose where the character shortly hands a pose before he goes into action.
It usually communicates tension and it's easy to tell what movement will follow next.On another note I'd try to implement some foreshortening to give away a better feel of volume and space.
Made you an edit for your 3rd pose:

in an animation your pose could be displayed shortly before my pose (where the hero crouches and then he takes the step before an attack) - my pose is just more expressive in terms which will happen next becasue it only works in 1 way. Yours works in 2 ways, since we don't know if the hero is falling back or taking that step of my pose.