After years of trying to care about the expanded Forerunner lore I still just can't. It's overly complicated, it uses weird counter-intuitive names for people / places / events that I can never keep track of, and the connections it has to the present day drama of the UNSC, Covenant, and Flood are only mildly interesting. The Forerunners were so much better as a mysterious background prop. Like, sooooo much better.
Edit : And Master Chief being genetically destined to save the galaxy cheapens his character so much. Man, I really don't like new Halo fiction much.