I can tell you that a modded Skyrim can use HDT Physics for cloth simulation.  Bascially it is weighted using specific names and done in a certain way and you get: dynamic skirts, dynamic hair (in terms of flowing and moving), physics applied to body parts (jiggle, etc).  That doesn't mean dynamic cloth sims are directly translated to a game engine but games have their own ways to simulate it.  You'd likely still need to use the creation kit for that game to pull off the designs.

Poser Game Dev isn't going to Re-topo, which is what you'd want to change the flow of polygons.  It will be able to convert something to low poly and keep the body part and material divisions.  For the most part its going to decimate what is already there.  I haven't worked extensively with it to give very exacting information.

There will be a lot of non-game uses for this as well.  Crowd scenes has been cited for figure combining.  Mocap via Kinect for Windows will be a great boon for animating (also Kinect for XBOX can be done but not "officially" - I've done it, no rocket science).  Decimation will have other uses, like reducing the size of objects (or figures) with massive polycounts, plus it keeps morphs (if you want) -- reduce that 500,000 polygon car model to something reasonable, for example.

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