More than likely they do have different teams working on different things all for the patch. Yoshi-P mentioned somewhere recently that I recall reading that he was going to start doing his checks in February for the 7.2 content. That's means they have to have their pieces done and ready for review and modification by that point. Which means this secondary team would have even less time and Yoshi-P would have even less time for review. And the main team would also have to worry about how the alternate team's code is going to interact with the code they're working on. This is why software teams have release windows. At my work, we can hotfix something if there's a bug or there's a small change a customer wants that we have done in the past. But new features and major bug fixes are always on a release schedule and we've fully tested them as much as we can before releasing to production.