Obviously, these documents have been in the works for some time - and one of the main things Pope Francis wanted to address when dealing with marriage. As stated in many threads before, there is a huge difference in how annulment proceedings happen from diocese to diocese and especially from country to country. In the US, annulment proceedings generally last a year or two (sometimes three), depending on the diocese and the complexities of the individual case. In many other dioceses in the world (such as in Latin America), annulment proceedings often take decades.
As Archbishop Bergoglio (and before as a priest), Pope Francis would sometimes ask divorced and remarried people why they hadn’t sought annulments. Their answers were generally, “It’s okay, Padre. My spouse will probably die before I get an annulment anyway.”
Also, the requirements and questionairres are different from diocese to diocese, and there is often misunderstanding of jurisdiction with annulment cases. Canon law allows an annulment proceeding to start in either the current diocese of the petitioner or in the diocese in which the marriage took place. But, knowing from experience, when my wife sought her annulment, even though it was a relatively easy case, it took her about 6 or 7 months for her case to be accepted by a diocese, because neither the diocese she lived in (Las Cruces, NM) nor the diocese she was married in (Juarez, Chihuahua, Mexico)wanted to accept her case - each diocese stated that it belonged to the other diocese. So she ended up with two packets - one from Juarez, and the other from Las Cruces (eventually, the diocese of Las Cruces would take her case). Still, though, the paperwork from Juarez asked many more questions (including questions about childhood, dating history, etc.) than the paperwork from Las Cruces and required twice as many witnesses (Juarez required six witnesses; Las Cruces only three).
So, I think the biggest purposes of these papal documents is to streamline the annulment process so that the process is about the same regardless of where in the world the annulment process is started, and so that a fair result is given that is thorough but also within a reasonable period of time (the length of time used in the US might be overly optimistic for the rest of the world, but a period of 3-5 years at maximum seems reasonable).