It's not a hard no, it's just that with limited resources and hundreds of feature requests, it's important to get priorities right. And so far it seems that maybe just a tutorial or something pointing out that you can do this might suffice.
I'm not sure it even deserves its own plugin type anyway. For example if you have an Enemies family, it seems convenient to have the EnemyType enum as instance variables on Enemies itself, so you can do things like Enemies.Monster and Enemies.Alien instead of having to make a whole separate plugin type for that (and a plugin that, as far as I can tell, does absolutely nothing except enable instance variables, which is confusing in its own way).