Built-in support for using constants (#define constants, not real constants) with .DMMs on instances.
When DM grabs the object tree, it could get a list of all of the #define'd macros and values for validation's sake. DM would store these values as their symbol name in the DMM in place of their actual value. When compiled into the DMB, it would simply get expanded into its value as expected.
This would allow us to use the NORTH/SOUTH/WEST/EAST constants for 'dir' (Not everyone will remember that NORTH=1,SOUTH=2,EAST=4,WEST=8) and cut out magic numbers for other variables as well such as unique (constant) ID to match up to a certain item in a list or something to that effect.