Familiar faces seem to pop up along with new ones. Is that really bad? Balance is the issue and what is unseen. Why not have a home land, conquer and defend it then seek other areas to explore and battle. Still come back to defend your home or perhaps spread yourself thin and give room for changes.
Last couple of days I've seen a DC guild on Auriels Bow, Dawnbreaker and Goldbrand. It was fun and challenging to have their presence although they do have a zerging short term mentality. On each of the campaigns there was boredom and some complacency in each faction, the incursions made things interesting. At the same time they integrated with those whose home campaigns were being visited. Not bad, more activity and varied challenge.
Is this a bad thing and if so, what would you suggest to keep those groups/individuals going back to their homes? If the dominating force is elsewhere, wouldn't that give opportunity to those not in power? If one side is dominating another campaign and an allied force comes to help, isn't that beneficial? Make changing Homes very expensive though.
Perhaps it comes down to Home rewards and benefits for defending.