Several months back, I remember reading a post or link about something like this. The idea of that you set a keyframe for where you want each foot to end up at a particular time. You then give Blender some actions it can use to get there. Then Blender would automatically calculate the pose of the armature so that the character would be seen stepping or walking, etc.
Currently, you can do something like this by:
1) making several paths and manually adjusting the values to make the character walk to different places - clumsy if you just want the character to take one step forwards or backwards
2) actually keyframe all the bones to move to the desired places in local space - that would mean that having to keyframe the movement for every step taken
If this was added along with a floor-contact mechanism, animation in Blender would get easier.
Imho, this would get solved and help in more situations with the ik it already has, and a pin bone to world space feature(I still think it's the main lack in animation). The floor constrain is nice, but you can do that thing with what I mention. Indeed, seems yet what animators in blender use is the typical empty based (I've done and used it) or nullbone rig. It'd be nice if it were a bit less tedious to do.
To hope that with some footstep it'd have enough to generate the pose and all ...I think it'd be much to ask, while with the other thing you'd already cover every situation.