I'll second Moogal, and elaborate a bit myself.

    RorrKonn, I don't play or make video games, but can you not see potential here, for "traditional" Poser use?

     Consider a scene where you want to populate Tink's Cafe'.  Imagine the RAM -and CPU cycles- you'll save by removing the underlying unseen polys of the filler dolls, combining doll/hair/shirt/pants/shoes into a single figure, and maybe decimating (reducing poly count) of the figure?  Wouldn't that be a boon to getting a heavy Poser scene rendered?  Imagine how much more manageable your hierarchy menu will be for twelve (fully dressed) background dolls, too.

     Do you have the time and skill to hand pose and keyframe a doll's animation sequence?  No?  Then consider the huge leap you gain by being able to capture yourself -and perhaps a more graceful friend- with a Kinect and then apply the captured motions to Rex and Roxie (or whatever dolls you're using)!   Forget about gaming for the moment - imagine what you'll be able to do in Poser, animating any action you want.

     Do you want to render in other studios or with alternative render engines?  Consider the RAM/speed savings benefit of being able to bake the doll's entire array of textures to a single map.  And any engine which uses FBX (Unity, et al) can get a rigged and animated doll.  It's like PoserFusion to... anything.

     And don't limit your game thinking to making a new game;  what about making yourself a custom avatar for whatever game you already like?

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

Silo Pro 2.5.6 64bit, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5