- 29 missions are too long for many players, who doesnt reached the final, so HotS is intendet to be shorter
- Surveys from Blizzard revealed many negative feedback from players, the campaign was too big, even coworker's from other teams said this
- achievementrate of finished singleplayer is low too
- HotS is planned with around 20 missions, still same amount of highlights like WoL
second part is about new units, so nothing new information at all.
I cant believe this to be true as i can remember Blizzard announced WoL and the Addons will have full content and dont feel like addons cause you can only play 1 Race at Singleplayer.
german source: http://www.golem.de/1110/87266.html
edit 2 polls: