If due to poor planning it would raise serious questions about how 343 operate. It doesn't seem to be too hard to foresee why having 5 games and DLC content on one disk may be a issue, or why similarly you need to plan for two disks.
The serious issue here is the level of inconvenience and the reason for the delay. If you have no internet you now have no local multiplayer, versus a small delay for all users (theoretically around just two weeks if its time from pressing the game and then shipping it). If they have separated the content to save a $1 on the extra disk (or even that...since they are buying Blu-ray disks at bulk directly) should have passed the cost to the consumer or taking the hit.
I can understand your point here, but again its about the most logical option. If they have to choose between the story versus the actual game content, then since the Halo brand was built and created by the Bungie games its the most fair solution to deliver the new experiences by download or release Halo 4 as part of a second collection. As it stands, no one would care about Halo 4, 5 or the Halo story in general, if it was not for the original experiences, and that original experience included multiplayer on the disk.