I think the prophet of truth, the prophet of regret, and the profit of mercy from the Halo series should be added to the Halo Mash-up pack.
I think they should be added because they are the main antagonists of Halo 2, and the prophet of truth in Halo 3. There are several skins of all the different species of the covenent and even different ranks of many species, yet their leaders are not present in the mash-up pack.
Even though the prophets have an odd shape and posture, they still have more of a humanoid structure than some other species that are present in the mash-up pack, such as the drone or the hunter.
I am also aware that the prophets are almost always sitting down and it may seem odd to portray them standing, but in Halo 3 the prophet of truth stands and walks for a long period of time with ease. So if you were to make them standing it would not defy and game lore or look very odd, and you could use the prophet of truth in that scene as a model. Unless you were to portray them sitting in their hovering thrones, but I'm not sure if that would be possible because from what I've seen, minecraft skins always have moving legs as they walk, or no legs at all. So it would not look right if they were in their thrones.
Please take this request into consideration. I think many people have also wondered where the prophets are in Halo Mash-up Pack.