I think the part about trading with people of similar levels is a good idea, but one question--why would a low level play, 15-30 or so, have a legendary? Most of them aren't high enough level to be fighting at the places where legendary weapons drop.
I like the thing about the friends list, that way they will have a little more time to think the trade through when they are accepting the friend request, and it encourages trading with people you know and trust.
Finally, for the thousandth time, some people find more fun in handling virtual currency to trade for their items than going out and looting them. For me personally, in LOTRO I accumulated 50 gold by level 40 because I found it fun to sell my items to buy better equipment from others. It wasn't as fun for me to go out and grind to try and fight the weapon or armor piece that I wanted. Maybe you like looting, I like trading, and I know there are plenty of other people that like trading too.