Kraxis has access to life and death because he can hire heroes from both sides. I don't think factions need much more differentiation. It would be a bad idea anyhow to start trying new features this late in the dev process. We already had a faction beta cycle and most people agreed it was successful enough until the expansion. Once modding opens up though, there is alot modders can do to add in even more content. Heavenfall already has another 8 factions that are almost ready and modding is still officially closed. I wouldn't worry about this sort of thing. 

For custom faction building, I am hoping that new modders come in and add around 100 or so new faction strengths and weaknesses. It's not something I find particularly challenging or worth spending my time on, but it would add some flavor for people who only use custom factions.