I will agree with you that Westgard should not have been placed where it was, but will stop about there. Placing it where Avernus is would probably have been a better idea.
That area was occupied by Arnor, so no, it wouldn't have worked.
Astrum gets credit for showing a lot of restraint: it could easily steamroll any opponent, it chooses to let other realms fight their wars and have their fun.
It's a sad day when realms get credit for not steamrolling opponents and letting other realms fight their wars without ruining them. I rather think that should be *normal* behavior.
