The tools are still there. If they do not show in your interface, you can add the Dynamics Motion Mode button to a toolbar from Tools>Customize>Commands.
Add Mass and Add Spring...
In a Pose I was able to RMB>New>New Spring System
So the tools seem to still be there. I've never used them and am not sure of their potential.
Bullet Soft Body? I'm not sure that's possible since Bullet animates the mesh to be independent of any bones it was attached to.
Maybe Spring System is for squishy meshes? I've never tried it!