I would pay to have weight painting tools plugin that I could use in 3DX
I say plugin as I suspect that not all would need to have such a feature. But some might want such a time saver.
Often that is the only time when I have to start over due to a slightly off weight painting problem that suddenly appears when animating that wasn't caught in the tests. Now if I catch a problem I have to go back to the software I use to edit the weight painting, export as FBX, reimport the character, set all the features and springs and tweak materials, and replace the character in the list and swap the character from the scene.
If I had weight painting tool in 3DX I could just edit and apply to iClone and would save a ton of time and work.