COD 4 leans are a joke. Its more of a side step really than a lean. Hopefully coroner can do something with that to make it more like tce without the pov issue.
Regarding the mappers, I intend to map for my own hobby depending on how the mod works out. A formal position is out of the question for me, but if all works out well I intend to make a few maps for cod4.
On a side note: Shouldn't it be fairly easy to port tce maps over to cod4? If so, technically you already have all the standard maps available for it with minor work. (hoping)
In my view the team producers only role should be to oversee the work being done on the official release by the rest of the team. Whether through advertisement votes or community packs. Which rarely happens unless the community needs an excitement boost of new stuff. The community will take of the temporary boost until and "official" update should occur. With customizations. But that's just my thoughts. Being a boss has its perks

The only issue with this type of team style would be finding the team members who would create the official releases with the knowledge of knowing they aren't being payed for it and final decision is up to the mod creator. But whose to say that other studios wont look at their work and try to pick them up for paying jobs. Thus, your work is minor after the first official release.