You're forgetting the use of the beta as a major sales tactic and enticement to pick up the MCC before December too. Plus, the way the game looks, and the fact they've been playing for a while, seems like it could've been done before the year was out, but spaced it to get maximum sales out of MCC holiday and h5 next holiday.
I'm not saying anything. People are just too optimistic if they're thinking that 343 would completely remove things like their new ledge climbing animations, Spartan abilities or smart scope as opposed to change how they operate, nerf/buff, tone down. 11 months out is a long time, but not long enough to reverse 2+ years of work.