Warlocks are one of the classes, if not THE class that got the biggest overhaul in this expansion. Every spec changed something radically. Warlocks are the only class (for the moment) getting an exclusive questline with an exclusive permanent (unless toggled off) change to their spell appearance that isn't related to a glyph, which is something unprecedent, even for the new shiny classes. Regardless of PvE or PvP performances, warlocks are the class that got the most attention up to this point in this expansion. Yet, a delay on this questline for one patch is a reason for this?
It's no wonder valid complaints are ignored when most people complain about trivial crap as this.