Well Daz3d did take a stab at game ready player models but never really took off as the fee covered the game use of an asset based off some of the parametric models they sell. They seem to have disappeared and have been replaced with the scaling licensing system.
As far as I can tell Daz3d is interested in providing their products to the gaming world as they do to thous involved in visual reproduction. Trust me DS is not just a toy for making bigger boobies <if that words gets through> and the DLC market is HUGE by compassion to any other market place.
As to usability Daz3d and DS should be on your must watch list as they do things fast and from time to time offer free software that supports their DLC market place and once they find out just how easy it is to get a DS model into Unreal 4 I believe we will see some action in this area.
As a coder who may need to have access to a “functional” asset this is good news as the rigging is the same for all their products with in the Genesis catalog so for sandboxing you only need to import the base model, which is allowed as long as you don’t redistribute, and then any additional imports can work with the same rig.
If interested in this option it might be a good idea to hang out at the DS forums as with out limits I bet it’s just a matter of time before that community switches and makes use of UE4.