The biggest problem with existing domain sales sites is that no distinction is made between a domain worth say $50, and a domain worth $50,000.
Great Domains came up with the right idea for domains over $100,000 and $1,000,000 but they stopped there, with nothing for the $10,000+ and $1,000+ domains.
I say:
Require appraisals for all domains listed.
Asking price required for all listed domains, no "make offer listings"
Asking price cannot exceed appraised value.
List separatly domains over
$1,000,000
$100,000
$10,000
$1,000
And please don't force a buyer looking for $2,000 domain to search for it among millions of domains worth under $100