Im pretty sure everyone knows most of the team would be working on BOM.
I'm pretty sure most people know that most of the team are working on aspects that will apply to the whole series.
What you don't seem to understand is basically only the Map guy, the Campaign guy, are working exclusively on the Sequel.
The people working on the the new graphic code applies to COD and every other sequel.
The people working on the AI applies to COD and every other sequel.
The people working on the FM applies to COD and every other sequel.
The people working on the DM applies to COD and every other sequel.
The people working on the Commands applies to COD and every other sequel.
The people working on the Sound applies to COD and every other sequel.
The people working on the Dynamic Weather applies to COD and every other sequel.
The people working on the Aircraft for the Sequel, some could also apply historically to the COD maps later time period, or just used there for fun.
The people working on the objects for the Sequel, some of those objects could be used on the COD map.
The people working on the vehicles, some will apply to COD, some to BOM, some to other theaters or time periods.
I'm sure I missed some people and features, but I'm sure most people get my meaning.