Only one 30 day campaign is a bad idea. A large chunk of your current PvP playerbase specifically avoids the large servers, because even with talented players and supreme coordination, your AoE caps prevent us from killing excessive zergs. If that's the only option, you eliminate the playerbase who came to ESO hoping for a wide variety of combat. It will just be 90 slamming into 90 for the duration.
While I am at it, 3-7 day duration campaigns are not incredibly radical rulesets. If you are going to change things, really spice it up. Don't give us a small number of servers and only let us choose how long we want to get our heads kicked in by zergs without recourse.
PermafrostGuild Leader of Ganked Againhttp://www.gankedagain.com
- Pioneer of the Tempchanter & Sturdy Dirty Healer Builds