What people are trying unsuccessfully to point out is that *all* the "filesystem abstraction" is is a mapping from a hierarchical name and offset into a memory address. That's all it is.
About that only thing you can change that about that and still have a mapping from names to memory is to change what the names look like. Maybe you don't want them to be hierarchical - maybe you want them to be flat, or multidimensional instead of single-dimensional. But there doesn't seem to be a good reason why changing how the names look is in any way related to NVM.