My first impression upon seeing Dwilight island is this is People fight against Environment. (PvE as some players may call it)
To watch the lands grow and ebb is part of the process. Of course those players who open dark portals causing more problems to humans, if many realms do not like those players, they can simply ban them or put bounty on their heads for their troublemaking activities.
Frontier realms should have some frontier feeling to it. Maybe frontier realms can seek other realms help; for you guard the front against monsters and undead attack on their behalf. In this way, both frontier realms and non-frontier realms can benefit from alliance, just saying one of the many ways which can benefit us all. It is up to our characters to solve the problems. If you think rogue problem is bad and your realm need help, ask other realms. Call it mutual benefits