Hi Sarsifus…
Yes the Mesh Smoothing is All or Nothing at this time. In the first releases of DS4 you had to apply it to each node of the figure, but that was changed to the base node early on. I believe the main reason for this was the amount of memory being used by all of the smoothing operations occurring.
You could try lowering the smoothing iterations to balance out your needs, but probably the best solution would be one of the available joint fix morph sets. There are a few different ones available. I believe ones in the Daz store and another at Renderocity.
Hope this helps… 