Heart of the Swarm Plot Overview

In this series of reviews I will be examining the plot of the various groups of missions in Starcraft 2: Heart of the Swarm to highlight retcons, poor plots, and illogical decisions. Where relevant I will compare SC2 to SC1.

My main issues with the overall plot of Heart of the Swarm are:
1) Weak motivations.
2) Weak plot.
3) Lack of mission variety.
4) Revenge plot is uninteresting.