Might be helpful to have a sticky with trade RANGES of the most popular instruments, just to provide some context about avoiding lowballing or markupping:

Some examples arbitrary, for illustration only....
UA SWU: 20-30K miles
AA VIPOW: 15-25K miles
if you continue to allow GCs....
UA miles= 1.5-2. cents
DL Miles 1.0-1.5 cents


Also, might be helpful to provide some popular published exchange rates for context:

1 SPG= 3 Amex
1 AA= 2 HH
1 SPG= 1.25 miles in many program per 20K

Point is, that there will be less of a need for third parties to critique trading offers if CC already has a reasonable (though certainly not exhaustive) reference point. Maybe the reference point could be a locked first post and have it be the gateway post to the proposed CC Discussion thread. The gateway thread could be updated and amended based on CC Discussion post feedback.