I've had some friends express frustration with the quest chain because they're the type of player who takes frequent breaks from the game. If you sit out for a few months it's very easy to fall behind, and then you're stuck running old content to play catch up. Quest item RNG was a cruel mistress to some as well. I was lucky to get 10 of each sigil at roughly the same time, but I know guildies who had 50+ of one type before getting 10 of the other. There was also the PvP portion of the quest which was not popular. I'm afraid to admit how many attempts it took me to get that Silvershard Mines win.
I enjoyed the cookies along the way: the sha-touched gem, the weapon socket, the metagem, the epic cloak, and then finally the legendary. It was definitely worth the time investment for me. What about you?