People who want merges already are the ones who least understand the game. Everyone who has posted reasons why it hasn't happened are spot on. We get cross server events and PvP later on, tons of new features/events/content to do in between, group bosses that allow you to farm new summons and all kinds of other things.

GNW is only one aspect of the game and one singular aspect isn't enough to warrant merges that will ripple through multiple servers. Plus, if you ever played any other web based game, you would know that after merges you actually lose quite a few people in that too. There are way too many downsides to early forced merges, a lot of which Ari covered, for all sides.

I really don't understand why people are constantly trying to have mods/devs push through content like that. There is a reason the game has lasted so long and that's because the development has been steady and consistent without forcing game breaking change. It's like literally nobody has even a little patience. Just wait and see how cross server stuff and future content shapes out before you ask for something as big as a merge.