My delusions tell me that there was a day when they made up craft worlds, Ork clans, and famous Imperial Guard regiments at the same speed and with the same amount of flavor rules that they made up Space Marine chapters.
My delusions tell me that fewer marine books would mean that I'd be more likely to be surprised by which army my opponent decided to bring, even if did end up being Super Eldar, Blood Eldar, Dark Eldar, Wolf Guard, Bad Moon Orks, Yellow Moon Orks, and Spooky Grey Guard.