I personally hope this feature comes to the game soon. Wonder Trading was one of the coolest things to do in the main games, and it would be really cool in Pokemon Go.
How it works is best explained by imagining 4 people all start a wonder trade. They choose their Pokemon to trade. Then they are randomly paired up. The 2 people in each pair trade the Pokemon they selected and each gets the other’s Pokemon. This could work for regionals, or just trading Pokemon that are common in different areas.
For example, someone in a desert biome could select rhyhorn, and someone in a coastal biome could choose magikarp. In the desert biome, Magikarp could be really rare, and it could be the other way round for the coastal biome. However, as they both traded, they now both got a Pokemon they considered rare for a Pokemon they considered common.
The system could give you 1 candy for the Pokemon you get, although my idea would be that you would unlock a Wonder Trade Key for every 500m you walked after level 15.
Do you think wonder trading will come to Pokemon Go? Do you think Wonder Trading in Pokemon Go is a good idea?