New delivery missions for letters and passengers are great. I sense there is even more potential to flesh them out and insert random effects and player decisions which will add much to both use of this type of missions and entertainment. And yes, some uncertainties and danger belongs into the picture, too.
(A) First of all, there could be a bonus for earlier-than-expected delivery, which raises your income. Say, every delivery under 1/4 of the max time period is eligible for triggering a bonus. The bonus itself would have to be random, depending on the situation and moods of your cus