Labels and comments go a long way to making an assembly project readable. I don't know how an automatic tool could interpret the human intention behind a label.
It's not that difficult, but I think the main obstacle is gathering and representing the collection of knowledge in a useful form.
There was a disassembler called Sourcer that would annotate code with a set of predetermined comments based on its knowledge of the PC hardware. For example a sequence of instructions that enabled the interrupt controller by setting a specific bit in its register would be identified and get the comment "enable interrupt controller". I seem to remember IDA can do the same thing, although it's been a while since I last used it.
There was a disassembler called Sourcer that would annotate code with a set of predetermined comments based on its knowledge of the PC hardware. For example a sequence of instructions that enabled the interrupt controller by setting a specific bit in its register would be identified and get the comment "enable interrupt controller". I seem to remember IDA can do the same thing, although it's been a while since I last used it.