We do lots of campaigns all the time, and only being able to pull reporting on them afterwards by placing them in a queue isn't ideal. We've like to see the ability to simply add to campaign as you're composing a normal post (as a drop down like queues for example), but still be able to post immediately or specifically schedule as normal, with the stats for the campaign it's 'assigned' to being able to be pulled through afterwards.

This would also mean individual posts accidentally omitted from a queue could easily be added afterwards to be included in the campaign analytics.