Why was dynamic batching of skinned meshes removed?

in Unity iphone 1.6/1.7 I recall dynamic batching of skinned meshes worked fine. Why does it no longer work in Unity 3.x?

Also, what is a work around? I have a game with ~50 game characters, many can be onscreen at once. All share a single sprite sheet and are animated/UV'd in Maya. They used to all batch and share a single draw call. Now they bog iOS devices pretty bad as none batch anymore. This is a project killer for me. I would like to explore work arounds.

1. Is there a way to use Maya to animate and set UV without breaking Unity 3.x batching?
2. Is there a way to still use Maya for animation but not setting UV and do that manually in Unity, or would that still be a skinned mesh? (I'm not sure what makes a mesh 'skinned'.

Any other ideas?