Menu thingies take up precious RAM. Anything in the kernel gets permanently loaded in RAM, reducing the amount for the unit's primary function of playing tunes.
So, when it comes to new features, I mostly don't put them into the default build unless there's widespread interest, or unless somebody the community really reveres has a nagging need for it (eg. Hugo, Patrick, Tony ..). Or unless *I* want it on *my* players.
The fan controllers are quite rare, so they don't pass that test, yet.