Elsewhere in the world they are clearly stated in AIP - and you don't need 15 levels of service in class G.
Erm, I make it four. One allows total autonomy, one points out traffic, one avoids traffic and the last accounts for areas without radar coverage. I really don't see the issue, unless your training is so poor that you don't understand it.
The other end of the scale is a system where I impose a certain service on you. the problem with this is what level should I provide? Control everyone as if they are VMC (I doubt the airlines will be happy with that) or as if they are IMC (most PPLs won't be happy with that)? Hence, as is appropriate, you are allowed to choose what you want.
For my benefit, could someone explain exactly what the problem with this choice is?