I'm a bit late to the proverbial party on this one. But on the Warhammer community website, it has been announced that the Horus Heresy will be getting their own rules set. This is not new, of course, as we have known about it for a while.
What strikes me is the replies on the Games Workshop Facebook group. When asked whether the psychic phase was going to be revised or not, there were a lot of non committal answers given. Why would this be so? Have Forge World or GW not agreed upon the rules yet? Are things in such a state of flux that straight forward questions like this cannot be answered? Or perhaps are we saving ourselves up for spoilers that will be revealed later.
From what was stated though, it is clear that the Horus Heresy rules are going to be an updated version of 7th with all of the needless stuff eliminated from the set. So entries like "And They Shall Know No Fear" will likely be removed from this rule book and other rules (perhaps a full explainer of "Primarch" rules) will be inserted?
In all of this, I'm somewhat torn. I do like the effort they have made to keep things in 7th at some level. But at another level, its really disheartening that the community has been split like this. I'd still like to play against Eldar using whatever set of rules we can. But should that be 7th or 8th edition? I no longer know. No one does. Until there is a 30k Eldar book released, I guess we will do what we can. Which will probably mean I write a space marine army list for my Alpha Legion. It will lack all the character that I have grown accustomed to though. Equally, this is a fate shared by 40k armies like the Raven Guard (or basically anything that isn't vanilla marines). Hopefully the newer 40k codex releases will give some flavour back to these armies and I can write some kind of army list for 8th that would be an Alpha Legion analogue (perhaps based on the Raven Guard -- hence my mentioning them in particular).