I have a gum squeeze bulb rigged with an armature (simple two bones), when I turn the bone the top of the bulbs vertex group is attached to I get a nice bending of the whole bulb. Please see the attached images.
Now I want to have the same behavior accomplished by shape keys. I found the Corrective Shape Keys addon, but can't get it doing a good job. The resulting mesh is a mess. Also I found the option to apply the armature modifier as a shape key, which gives me exactly the same result as with the armature, but instead with a single shape key. That's too good to be true. So I found, that when I want to bend the bulb in +X/-X and +Y/-Y after the first time using the armature modifier as shape key, my rigging has gone and I can't do the -X/+Y/-Y motions with the "use armature modifier as shape key" process...