So as we know, you can have up to 300 people in one guild and they can create an
alliance of 4 such guilds that have enough bonuses to effectively act as one single mega-guild.
So my question is - what's to prevent a 1,200 member mega-guild, or two, from completely taking over the server and ruining the game for the rest of us? No node competition because they can just take what they want so the rest of us are only left to control the scraps with nodes they don't want. No real ability to successfully siege a node or a castle because hey, they have 1200 people to defend it. No real ability to contest world/regional bosses, caravan trade routes, dungeons, anything.
Even if you don't want to contest those spots, but are more PvE oriented and merely want to go through a specific dungeon or kill a certain regional boss for their loot - if this guild decides it's theirs, they can camp it 24/7 with their tons of members and you'd never get a chance at the content.
If you're in one of those guilds - do you really expect to have any real competition? If you like PvP, you're not going to get it. You're just going to steamroll people which isn't fun for you or them.
Am I missing something key here or is this a massive game-killing flaw in the system?