>Why would it be good for this to be exposed inside a container?
So that applications know, if they can use advanced features such as AppArmor or not. And to give more complete environment for the admins.
Plus, to debug problems inside debian-installer. (it lacks /boot/config), like bug # 783982, where normal Debian 8 kernel supports floppy /dev/fd0, but d-I kernel doesn't.
Why it can't be changed in stable releases? I mean if the change is small and beneficial, why not ? (Assuming it doesn't require major kernel source code changes, but only kernel config)