You have to somehow generate all the random seeds in exactly the same way though right? Perhaps it was getting to the point where some of the stuff in the backend that needed to be randomized was too difficult to replicate.
Halo 3, ODST, and Reach already do this. You determine the seed once at the start of the session, and that determines all the dice rolls for that session in exactly the same order. This allows both films and online co-op to work, as the AI will make the same random determinations in the same order with the same inputs. This is what its going on when you see "deterministic AI" (which only Halo 3 onwards has, Halo 2 has some remnants of it in their attempts at online co-op) or "deterministic networking" (Halo 3/ODST/Reach campaign and Firefight networking)
Right, but wouldn't you have to allow enough memory for Theater to run itself and also "playback" the code? So removing Theater as a limitation would give them X amount of extra memory to do Campaign stuff?
It only loads the immediate buffer it needs - confirmed a while back by Bungie that films can get as big as the biggest 360 HDD (when someone was asking how long an ODST firefight film would keep recording for). So we already know gigabyte plus films will be loaded.
I have three plausible speculations in mind.
1) Simply cut for time. Boring and heartless explanation, but it happens, and the most likely.
2) The new Forerunner AI was not made deterministic. But that wouldn't make sense since campaign co-op over Live wouldn't work under lockstep if it wasn't deterministic...... unless campaign networking is no longer lockstep. I think I just confused myself.
3) 343 may be planning to more aggressively update Halo 4 with Title Updates than past titles. Under this plan, it would be harder to maintain campaign film interoperation between versions, as they don't have the luxury of just loading specific Megalo hooks. It would, IN THEORY, be easier to just drop films in campaign so you no longer have to consider them in title updates. Bungie's interop of old films in 3 was a considerable undertaking. This is 110% pure speculation though.
This is of course assuming campaign films are even cut.