I think part of the idea with that was to make brenner sort of like one of the WoW battlegrounds (e.g. a super simplified alterac valley) the thing is, people only go into the brenner area to duel without having to spend ballista points to reserve the diorama-ghelsba. Thus, they only get in the way. (Aside from that, it's hard enough to bust open the flammen brenner without having to kill the posten first- but at lv90, the postens are still 75 and they're really just free TP)