I don't mind the "short" (it's rather subjective if you ask me) mission count. I think it actually suited and focused the limited story that was HotS. It moved along at a clip and was over before the poor taste could linger (for some at least). Compared to WoL, the mission bloat was fun to play through but the story was so bloated and disjointed it felt like a pointless slog until the final series of missions and exposition were just unceremoniously dumped onto you.
Here's hoping that the short mission count is accompanied with better writing in LotV.