I had a suggestion but I have no idea if it could be implemented or even desired by the wow community. I figured this would be a good place to test the waters.
Change: Allow trading cross realm in the dungeon finder.
Why this change is desirable:
For lots of people, myself included, gold serves no purpose other than to bribe the lucky winners of items we want. Everyone has their price, having the power to negotiate for drops is only possible with currency. In LFG, currency is taken out of the equation thus making it impossible to trade.
Think about it, the Zulian Panther drops that you have been grinding for. Sweet! You roll and lose...awwwww But wait! You can bribe the lucky winner :) That lucky winner doesn't give a darn about mounts, in fact he is extremely happy to sell it to you for 10k. Its a win win.
Or this...a rare boe or recipe drops. What if the winners prevailing market value for the item is less than on your server? You pay the winner the market value of their server and you sell it for your servers going rate. Win win.
Extremely difficult to code? Not sure if it would, you can trade items that drops in the dungeon, conjured items....other stuff? Why not gold?
Blizzard concerned about effects on separate economies? Unlikely. They allow cross faction trading already and those two function as independent ecosystems already...
I don't know how others feel but feel free to add to the discussion.