I see a lot of people complaining that hardcore WvW guilds are going to make massive alliances, but the reality is WvW focused guilds are some of the smallest guilds in the game. I'm sure you would be hard pressed too find a WvW focused guild (who run comps and coms and have set schedules) that could roster 50 unique players to select them as their WvW guild, once you take into account that most of these players would run 2-5 guilds. So the "Hardcore WvW Guilds" even at the speculated 5 guild max you would likely not get more 250 (I suspect a lot less) in such an alliance, which would be approximately 10-12% of a server. In addition most WvW focused guilds want some form of competitiveness, stacking into "mega alliance guilds" doesn't make sense. Most people I've spoken to in these types of guild have said they would want an alliance spread out across multiple time zones to help create a stable backbone of commanders for the communities they would be put in and accommodate their members in multiple guilds. How to avoid stacking has also been a topic of great discussion. The bigger population alliance are going to be made up of less organized, no requirement guilds, PvX guilds and community guilds. I believe this 500 - 1000 limit is more to allow for these type of players. It is going to take all types to players to make new servers and the new system work and I believe that Anet is trying to make a system that will prevent stacking as much as possible. Note: I still have concerns over how small guilds will fit into the Alliance system.