Well, most definately the problem of loss of culture would arise, but only temporarily. There would be only one culture, and the next generations would take it as their own. Eventually, we would be one united race, culture, etc.

I don't mean one country (USA, for example) taking over the world and making everyone change to our culture. I mean everyone losing their culture, to join as one culture. Rather than having individual countries who have their own ideals and agendas, have a single race/nation set on improving humanity, living conditions, etc.

As long as there are differences, there will be conflict. Until there is one unified entity, we're just holding ourselves back unnecessarily. We're not seeing the true potential of the human race.