The more I think about it, the more certain I become that Earth-616 as we know it is Moira XI and that we will rejoin it with Dawn of X. Obviously the whole point of PoX is to prevent it, basically meaning she has to die again for another (final) try. And while PoX might be Moira IX, I suppose, HoX - which is clearly Moira X - lines up perfectly with it so far. This could also make "our" Moira a baseline human again (albeit probably still with her memories of past lives), and would prevent future writers from having to deal with the implications of her reincarnation power as an ever-tempting reboot button, making death and resurrection for her no different than for your average Big Two character. Yes, what little we know of Moira X's timeline from this issue is extremely close to what we have seen in publication, but we all know how awkwardly HoX #1 gels with what has come before, and maybe it all went according to plan safe for one crucial - upcoming? - moment, so why would she change much if anything up till then?
Obviously it's gonna be important. And my personal guess is that for some reason she can't remember it.
Yeah, this arguably is happening on a different level, but come to think about it, my theory would also fix this conundrum.
I guess in this special case causality would still be preserved if her death hits a universal rewind button, but I'd rather Marvel don't add another exception to their beautiful, simple and sensible time travel = alternative universes rule. Also, this would mean that the children of her happy first life don't exist anymore anywhere out there, which would be extra sad, and that Irene basically knowingly killed herself when she had Pyro burn Moira, which would be rather moronic of her in my not so humble opinion. Finally, if Kang etc. don't take note of her conscience jumping to another - freshly created - universe with her death, that's fine in my book. If they don't take note of her rewriting a whole universe - and one of their favorites, to boot - from the time between her conception (relatively close to the big bang on a cosmic time scale) until its heat death, however, that strikes me as rather hard to reconcile.
Possible, but she seems to care much more about the big picture at this point.