In the future, will missions be capable of having multiple paths to follow, with different kinds of compensation for the different paths?

Yes, such as with what was mentioned earlier regarding the P.I. Wanted mission, where completing the mission as-is could give you less money than if you took payment from someone else, to only reveal information that either made someone look innocent or guilty. Generally speaking, it is something that they want to do, but it would be a more complex mission than they currently have. This is because right now they're trying to build what is more like the ingredients of a mission - at present the missions aren't that complex because they tend to build the objective first, and string those objectives together to get a whole mission.