I like the idea of war deccers having to anchor a structure of somekind for each war. The anchor mechanics could mirror upwell structures but with fewer rf timers (or none at all) and destroying the structure will lead to an immediate end to the war.
Defenders who want to fight back would have a focal point where they could get an actual fight. With the right placement restrictions (eg max number per system, 1AU minimum distance from stations and citadels), attackers will no longer be able to just camp gates and trade hubs but would be forced to and warp to the structures to defend them in order to keep their war(s) going and to protect their investment (presuming each structure will have a considerable cost).
It would also be possible for groups of defenders to band together to attack the respective structures that would end each others war decs and for alliances that wardec 100s of corps, defending these structures would thin out their resources and prevent them from all waiting at choke points for easy targets.
At the end of the war the structure would go inactive and have to be scooped and redeployed to be re-used for another wardec.
Just an idea.