The world in Starcraft is chaotic and constantly on the brink of destruction, whether it be from the Zerg swarm encompassing everything or the god-like Xel'naga planning on destroying everything to ...
It is a big one, we can talk as much as we want about graphics and effects, but the biggest issue is and always will be the new and modified units. From the Terran we have: SCVs, Mules, Marines, ...