Think that is still too vague, though. I personally do not believe that every Exotic should have the same value as another Exotic. You need an element of supply and demand in there, too. For example, SGA is pretty much universally panned, while Gjallarhorn is pretty much universally praised. A straight trade on those two items would not be fair, because even given the same supply, SGA has nearly no demand, while Gjallarhorn has a very high demand. Then, take it a step further, and Xur sells Gjallarhorn next week. It is still in more demand than SGA, but has in increase in supply. The value should drop, until demand outstrips supply again (not to the point of SGA, but somewhere in between).

While this is true, who would ever agree to this trade if they had the Ghorn? Could be used to leverage a much better deal, like a vex or IB

That is the loophole that people would use to monetize trades. It is not about the sincerity of players and how they will value items, it is about human nature trying to game the system. "Sure, I've got three Ghorns. Just shoot me an SGA and $20USD into my PayPal account, and it is yours." The funny part of it all, is we would then likely see people complaining on here about: "I traded a Ghorn to this scrub, and he didn't send me the $20 that I asked for." :-)

lol then I'd say he got what was coming to him. maybe he'd value his other Ghorns a little more haha

True. :-) My opinion is that you will not see a system in place, if it can be easily exploited - solely given the bad PR it will generate, on top of the bad PR that already exists. Would love to see a real trading system, but they need to build it on an in-game economy that is not robust enough to support it. Sake of argument, say that you need to make both sides of a trade be within 10% of in-game value and that Ghorn is worth 5x the amount of SGA. One to one trade would not be allowed, in that case - because it benefited the guy with the one SGA on the table. Eliminates the farmed out aspect, at least. If he had five SGAs to trade, then the system could allow it - but if he offered six, it would be disallowed again, because the trade then benefits the other party. The tricky part is figuring out what the multiplier is, and the fact that it will change over time. Plus, if you are just outside of that variance, do you allow something else to be thrown in - i.e. one SGA, five Motes, and 4,000 Glimmer? If so, than you need to extend the economy to everything - weapons, gear, consumables, etc. Just watch the Bungie job postings for someone with a background in Economics. Hehehehe... :-)