I think it's a very good idea because it will reduce the pressure on the core development team about feature X or Y. "You really want this feature? Write it as

I think it's a very good idea because it will reduce the pressure on the core development team about feature X or Y. "You really want this feature? Write it as a module." Then it can serve as an incubator before importing functions into the core library. The only problem with modules is that poorly written modules may cause unstability. One way to mitigate this is to have some sort of fuzzer/stress tester for developers to test their modules against.