First off good job Olivia! I also share your concerns about Wow movie being a flop, not because I believe Blizz would screw it up just that that masses would not get it. I think what they could do is split it like the Lord of the Rings or the Hobbit. Actually tell the story behind all the expansions. The first movie could be about Kaelthas and Illidan. (We can skip about Molten core and even Blackwing Lair because that lore was touched on in Cataclysm). I would love to see a cinematic of Exodar crashing into Azeroth in 3d.
Second movie could be about Arthas, and 3rd movie would be about Deathwing, touching on the lore from Blackwing Lair and Oynixia, Dragonflight and Thrall and so on.
As I am writing this what I think would suit Blizzard better would be an anime like series similiar to Star Wars The Clone Wars.
If that is too much of an undertaking I think the story behind the rise and fall of Illidan would make a good movie.
About the new client I suspect that you may be on the money regarding it allowing cross-game/cross-zone chat, but I also feel that it will have an upgraded Warden (Blizzards anti-hacking program) Hacking has been strife as well as botting and regardless of Blizzards best efforts it hasn't really slowed down much. So I wouldn't be suprised that the new client would be boosting some new type of hard core security.