I actually like all of that.
The more complexity the better.
It's the only thing keeping me interested in Halo.
There is such a thing as "too much".
I don't want to know about the Forerunners. I want them to be a mystery that we get hints about, but are ultimately still dead. I don't want to know about any new SPARTAN programs, because it keeps taking away the importance of the Master Chief in terms of what he is for the UNSC. I don't want to see Halsey or any of the other expanded fiction characters, since they have their own unique and complicated stories which there simply is no time to explain in the Halo games. When you add those characters, you are essentially blocking off half your audience since they don't know who they are or why they are important.
Halo 2 was my favourite game in terms of story, with Halo 3: ODST in close second. KISS; Keep It Simple Stupid. The story was expanded in #2, but it was still easy for anybody to dive into and understand. Everything from The Storm onwards in Halo 3 confused the stuff out of me. Halo: Reach is also easy to understand, but it introduced SPARTANs like the UNSC was buying them from a vending machine and there was a lot of background fiction that had to be rushed through.