Blender has a confusing (and probably inefficient) way to handle collision shapes and rigid bodies.
Bullet Physics is the physics engines used by Blender and many other games. It supports btCompoundShape() to easily create efficient concave shape by aggregating primitive convex shapes (box, sphere, hull, …). There are other efficient collision shapes supported by Bullet, like btMultiSphereShape().
Blender does not seem to use Compound Shapes or other efficient shapes. When there was Blender Game Engine, it was possible to set collision shape as Compound and aggregating the shapes as children of a common parent. But now BGE is gone and there is not even the option to set a collision shape as “Compound”.
Furthermore, there is no way to export a simple .bullet file. I previously used an old add-on for exporting rigid bodies but it relied on BGE.
A redesign of how rigid bodies, collision shapes and constraints are handled can be very helpful for users that use Blender as an editor for interactive applications.
If Blender let users export this physics data, it will greatly enhance its usability and interoperability with external application and game engines, many of which are forced to recreate all physics and collision data.