Personally, I could see it as boring if I just played the game alone and only did dungeons with randoms, but once enough of my LS mates hit roughly the same area of progression, we've had a blast running the usual dungeons. It was a tremendous change when the random pug element of the DF was taken out of the equation and we all knew each other and there was no anxiety over getting yelled at. In fact, I just completed my first AK run yesterday in nothing but AF *queue screeching violins*. We only wiped once on the first two bosses, and beat the final one in one go. (I was the only 'noob' in mostly AF, and I was the healer, though I did have 2 darklight pieces)
I can understand that a game shouldn't have to rely entirely on playing with friends you've made in-game to be entertaining, but the way it changes what many call a dull and boring game into something entertaining, I guess you could say... *sunglasses* Friendship is magic?