Please make the single player campaign epic, i was disappointed in MW3 that it was so small with hardly any massive battles to give me the feeling like i was a tiny pebble in a massive storm. i also enjoy the emplace weapons as well with high tech weapons that lock on or launches lots of missiles. the last stand scenarios in the single player was cool as well. maybe have it like freedom fighter where u pick what side missions u want to do then after u do them u get access to weapons or support. more support tools like that artillery strike would be good as well, maybe orbital bombardment as well.
lastly please make sure single player story links up with the rest of the books ect.