There is "making the game to easy" and "wasting time on camping a NM"

Very few of this NMs drop anything thats worth it, so you can at least be sure there are no item campers.
Some NMs share trials, and there still are douches that wont team up with you.
Some NMs have a HUGE roaming area, so while you are at the one edge of it, there is a possibility it spawns on the other side, and maybe even is killed by some passer by.

To make this more easy, and less annoying, they could at least take nms with smaller roaming areas. It would be awesome if you had a hint section in the moogle almanach when it was last killed/if it is about to reappear/if it just was killed.
I knew a "botter" (SE got him good and banned him, serves him right, didnt go NM hunting with him very often because I dislike cheaters) that somehow knew where the NMs deathspot was and most of the time, and saif it this spot dissapears, pop time is near. So the game does seem to have this data somewhere.

Why not make it like this:
Its not about to spawn soon: It seems like something evil is lurking in the shadows.
It is spawned: Take care, something evil is roaming freely.
It got killed very recently: The evil has been purged.
Longer time to spawn: The shadows grow darker and the feeling of dread is rising.