I think I'll be inexplicably upset if they don't have some comics and books to explore and expand on the world of Arakko. Besides the world they already have some interesting characters that I want to know more about like Isca the Unbeaten, Tarn the Uncaring, Solem, Genesis. So much richness and possibilities there. They don't necessarily need to cross over and they have the freedom to tell brand new stories in this new terraformed mutant world on Mars (though I want to see some more stories with Solem - Wolverine and Genesis - Apocalypse, for example). Arakko also supposedly has a lot more mutants than Krakoa. I'm not even sure what Krakoa's population is, but Arakko is supposed to be more.
I also might be the only person who wants to see more Hordeculture.