The Cantha guild hall was marketed to be obtainable by small guilds (without having to recruit unknown people to help). It was marketed (specifically by Ruby, even) that even 2 people could capture it as duo. Unfortunately I found this to be quite untrue at this moment.
I tried twice (and yes, my DPS is pretty good, as is my friend's). We had a good time on the regular mobs (trash mobs), they were all fine, but the bosses took up to 10 minutes due to their extreme amount of hitpoints. We could keep breakbars down most of the time, but even with that it wasn't enough. With 4 bosses to kill (and time to move in between), 40 minutes isn't cutting it.
I hope this will be tuned, because I was looking forward to claiming this guild hall. It's a private guild hall (just friends) and only one other person is currently playing the game.