Ok, so we know that some players will always have all the toys. And that the
fort system is stagnent right now.

If the defenders get the advantage, why not have role reversal.

Make it so you get rewarded for raiding forts, not keeping them.

Idea:

Each player can only control one fort, once they control a fort they can go
raiding other forts (perhaps with players being able to build their own forts
like citys).

Forts don't give gold, but some sort of rep for successful raid.

Raiding would be going to someones fort, smashing the defenses and
wagon-training the loot back viking style.

The return to your own fort could require a certain amount of land travel
where there is the posibility of getting ambushed (ooh, a use for the
outerworld...)

Once you get the loot back to your fort you get rep.

The quest would be given for successfully raiding all other forts without your
own being raided.

Getting raided would lower rep some.

The more guards and buffs you have on the fort, the more rep you loose if you
get raided.

Each fort can only get raided once per 48 hours?, or some sort of restricting
factor - you get to the fort and find it's already been raided ... DAMN!.