Nitpickery Extreme -- Starcraft 2: Heart of the Swarm

Hey y'all.  Spoilers do here abound.

It just occurred to me the single biggest reason why the plot of Starcraft 2 ultimately failed.  The thing all the fans loved about the earlier games was all the political tension.  Lots and lots of it.  As the game stood at the end, few could be trusted.  Protoss authority was almost entirely annihilated, in both the loss of the Conclave, Raszagal, and Aldaris, as well as the disappearance of Zeratul.  The UED's hand in the K Sector has been destroyed, and there's no real telling what Earth will do next.  Mengsk, the main human leader, is clearly mad with power and unable to be trusted.  Every single person in Brood War ultimately failed because they never, until the very last mission, realized that the ZERG are the real bad guys.  And by that point, you've already done the secret mission and found out that the Zerg/Protoss hybrids exist, and that they're even worse.

So what that boils down to is that the hybrids and Zerg have to be dealt with, with the possible interference of Mengsk and the UED.  Four distinct threats, two of which absolutely cannot be ignored.  The hybrids and Zerg are the worst, as the UED isn't a race of murderers and their influence may or may not happen again for some time, or in the same way.  Mengsk is stupid, and if Raynor's treatment of him in BW is any indication, he's easily manipulated.  However, all four are still threats, and the addition of Valerian means a total of five.