Top 5 <X> (IMD, Linearity, etc) at $10, $50, $100, $500, $1000, etc
But what we're really doing is
merology here; so if we want broad cross-domain validity we need to understand how the domains relate to each other generally.
What are the things that technically define a component?
How do these things externally present or interface with the next temporal sequenced thing?
Then run the whole thing backwards for path optimization and test if there is measurable improvement relative to previous models/standards/methods.
How is digital or analog information encoded?
What does a source need to do to generate a digital/analog signal from digital/analog encoding?
What does a DAC need to do in translating digital encoded information into analog encoded information? (Digital clipping, etc)
What does a DAC or component source need to do to create and manage an analog signal?
etc.
Then you get into the ends of the chain with physio/psycho-acoustics, general user interface and design, part longevity/maintenance, aesthetics in function or form (which are heavily influenced by broad socio-economic trends and purely idiosyncratic situational needs), etc
The full scope of ASR is huuuuge. But we can get a good enough model for most people without having to go to that length (or at least offsetting some of the computation to the end user).
What do people mostly hear?
What mostly bothers people?
What mostly pleases people?
How can we find measurable targets the correspond to these?
How can we make what they hear mostly the latter and not the former?
What parts or designs lend themselves to generating the good and suppressing (or at least not exacerbating) the bad?
Which products use these designs and parts AND which products correspond to the measurable targets?
How much are they? What is their availability? What is it like to own and maintain one?
If we can answer those questions the top 5 for whatever category you choose should be sufficient for almost anyone. If you list the top 50 people should be able to figure it out for themselves if the data is accessible and sortable.