The folks at Relic heard the criticism that most of the missions in the single player side were a bit too similar and have pledged for more mission diversity in the game. The campaign will also get some replayability with the new Chaos system. In certain missions you'll be given choices about how to approach a situation and how you react to that will govern your level of Chaos. This is important as you'll gain extra abilities depending on how chaotic or good you are. The key here is that you should pick one path or the other as you need to rank up on one side to get anything useful.