i don’t think that beacons itself are sufficient protection in an open world in particular when it comes to joint building.
if we want something like towns (like forming on GORTNEN) we need something that is more dynamic than beacons. at gornen we have streets that are totally unprotected (and i’m sure nobody will use beacons for them) and we have streets (in the marked district) that are shared between two players [one on the right, one on the left side]. the shared streets work only because there is a tacit agreement that everybody has 1 block street around his marktplace.
some time ago i (and a lot of other players) helped out cleaning some mess at Ruchs capital. Even though much has been protected by player beacons, a lot of space has been destroyed and flooded with blocks. The griefers have also tried to wall in the beacons WTF …
[quote=“Zouls, post:2, topic:3364”]
big guilds who would claim a farm spot without putting down a beacon and then just instant banning anybody getting near it[/quote]
if the town founding is expensive and takes a lot of time, and if it takes time to become an inhabitant of a town, where is your problem ? a guild may claim land and farm … if you get banned from that “town”/claim go along your way and search some other space to farm. the scenario you describe is a bull ranch … if you go on the ranch and kill a cow the owner will be very unhappy with you too 
EDIT: i’ve made an edit to the initial text to make the concept of a “town” more understandable. towns in my idea are “dynamic” beacons (protect stuff agains “random player”) but can be accessed by everyone who wants to join but with restrictions (like wait times). therefore you need a dynamic system to manage the players and protect town.