Oh, you mean like a Global Trading System or Wonder Trade? That could be interesting concept, though idk how the staff feel about taking the time to make the servers different.
Exactly. Something that might not necessary require two players to be active at the same time. It could be like an auction house.
Making the servers different in a minor way would be a huge motivation factor for me. It is like the people who buy both original pokemon games because of the few exclusive pokemon in each version.