Yes. I believe some dev from Bungie even said after that it was what they intended, maybe on HBO or another place. 343 chose to take it a different route. I do feel that the earlier way was better. Allowed there to be some mystery for humanity/covenant/forerunner. It was why humans were so special, why the Prophets were deadset against them being allowed into the Covenant etc
I wrote the Librarian stuff quoted in the OP.
There were lots of ideas about how to continue the threads from 1, 2 and 3.
There was no plan carved in stone.