How so? Most of the hate toward Warcraft and it's story now seems to be misdirected hate coming from peoples ill-feelings toward WoW, instead of actually being based on serious problems. It just looks like fans are angry that Blizzard made a game that doesn't cater to them, and decided that now everything WC-related is "bad" (to put it lightly).
(As far as Blizzard and story goes, it doesn't look like much has changed, except that they now hire more writers and release more books. As for the WC universe, it also simply looks like fans are less forgiving now that Blizzard is "popular". I mean really, how many times have they changed Medivh's story before? His character alone has given birth to more plotholes than many other series have, yet fans didn't really seem to care until now. They screw up the story every once in a while, but they always did.)
I'd like to know the reason in particular why you feel like they ruined the story tho. (maybe I'm just biased)