I think it would be really cool if they made a way to run both games together, this doesn't even have to be for VV3, it could be a type of expansion that you can use. But basically you can run both games together, see both tribes and take care of them. Maybe have the two tribes interact in some way, like manage the politics between them. This way you can still play with the tribe from VV1 and the tribe from VV2.