This has been the case more or less since Spring first launched, and as much as it has progressed it's hard to see quite how it will ever change. Perhaps I am overly pessimistic. There have been various attempts over the years (i remember someone running an animated Quake model many years ago and jk's shader based shark animation) and with the big upcoming changes away from the FFP and towards shaders perhaps the time is nigh afterall for an easy to use framework that can link in with the existing lua infrastructure somehow.
As I stated in the Art Forums, I do have a workaround to allow people to use bones, but it would only work for Maya (and possibly Max - Max handles constraints differently than Maya and I focus solely on Maya now) and not in Blender, at all. The problem is, I don't know how to label body parts to get them to work, nor do I know all the animations needed to not break the game and I have no way to get them *IN* the engine, as it's beyond my ability, for now, to make a test bed. It's also pointless, if blender won't use burned keyframes from a dae file.
Keep in mind, this is all theory craft. However, if it *DID* work (which it honestly, should), It would be as simple as my creating a humanoid rig, chicken walker rig and then a tank/turret rig. Then, anyone could just parent their mesh parts to the base rig and use prefab animations. Easy peasy.
I'm trying to find something that I can basically clone the MC2 engine, but with more modern features. So far, out of all the ones I've seen, Spring is the most robust for what I want to accomplish. I'm probably going to have to break down and go back to learning code again. XD
To produce a workable game that is not just Total Annihilation you will have to do some coding, for sure. It's hard to see how that barrier would not be present in any other engine though - but perhaps not a barrier to artists (i.e. animators) in other engines.
Being from the Industry, I guess I'm just used to having all the tools I need accessible. That or it was just simple animation projects in Maya that are passed back and forth between departments. I do the animating, after a rigger (or myself) built the rig, I scrub it to make sure it looks clean and then it's off to the VFX guys, before final touches by the rendering team.