I’ve got a feeling we might be seeing the return of Johnson on Installation 04, seeing how he made his debut in that level on CE. It doesn’t make sense to include ODSTs (which weren’t even in CE) and not include Johnson.
In this video: http://www.youtube.com/watch?v=mJC5z5CNfoE at 2:05 Dan says the AI is none of the above for the FF map meaning they had to make a new, different code since Johnson was isn’t in Reach.
Just a little speculation.
I’d weep tears of happiness.
The A.I. are Reach A.I., not CE’s A.I. So it is highly unprobable a Johnson NPC will make an appearance, considering 2 or more Johnsons (the Firefight voice) would be weird and creating an entirely new NPC for the sole purpose as an Easter Egg would be extremely redundant. All 343 did with these ODST’s was take them from the original game code and popped 'em in an A.I. friendly environment and gave them new stage directions, nothing monumental.
More good news: http://www.youtube.com/watch?v=tFq-___D7HU at :50 David Ellis says we’ll see a “familiar face” in one of the new maps.
JOHNSON IS BACK! He has to be.
Did you read Halo:The Flood?
ODST’s were on installation 04 but just weren’t shown in Halo:CE since at the time they hadn’t been invented, I’d love to see some ODST’s in the anniversary Campaign 