Don't understand why campaign isn't just a hardcore MP training mission, the kind where you could say, "If you master this, you're ready for online play." Something that shows and teaches the ins and outs of the maps, proper techniques for Rush/Conquest strategy, getting to try out all the weapons, kits and classes on each map, etc.
Seems like such a thing could only do wonders for the online community's overall noobery levels; instead of learning the maps and dicking around in a live match, players can get all that out of the way in the "campaign"; by the time they go online, it's all "Ah, I know just what to do here" moments instead of trial-by-fire/learning-on-the-fly in ranked matches.
