It would be an invaluable resource for those who dabble in the second-hand market (I would love to see an archived review of the Dali Suite system, for example), but presumably also a mammoth undertaking for WHF staff to get this volume of information online; and therefore ultimately impractical?
There are relatively good bargains to be had in the 2nd hand market, and prospective buyers from these forums need to be guided accordingly, so it would definitely be helpful.
Yes, it has been discussed many times before here, and while it would be desirable and is certainly on the wish-list, at the moment we don't have the resources to prioritise it.