In Starcraft 2 the starting probe/scv number is 6 not 4 so this will result a rapid development of technology or unit production.Starcraft 2 has more flexible units and strategies with reducing extra focus from the player.The units are more smart and more automatical while the unit complexity increases and the strategies will change with these effects ofcourse.The main tactic must be well designed to stand at war,I think the human factor is decreased like all technological developments.But if your main tactic is strong your fail probability will decrease drastically.In the video you can watch from www.Starcraft2.com, the pressure created on the enemy has very critical effect to control the game easily and which brings you victory.