As far as I can see conquering settlements are hard to achieve without a really organized army yet sometimes even that is a bit problem for an attacker side. My recommendation on this topic is basically to let the holder of the fort be the defender.
Most of us already reached level 60 and we’re only doing elite areas so guilds are able to afford to leave people at forts to defend to deny attacker side to obtain the fortress before the war and earn some time for their guild to come to the fort to defend.
This recommendation will also affect other players who are not able to get into the wars because they’re not in the guild and it will cause a big scale war between factions to obtain the fortress.
I think this revision on the fortress system will heat up the battle system and other people who are not a part of the big guilds will have a chance to have fun with everyone.