I think (and kind of hope) that we might be slowly progressing towards an era where we stop discretizing gender into specific labels. The ever-growing number of labels suggests, to me at least, that we've got a wrong fit for the data type. I think it's rather simple: a multi-dimensional continuum of gender identity cannot be reduced to specific names. But that concept of "discrete gender" is very well-entrenched in society, so there's an attempt to make it fit by adding more discrete categories.
I'm not sure this is "wrong" given that I don't think society/culture/whatnot ever turns on a dime. But I don't think this represents a satisfactory state.
A good place to start is to stop asking for "gender" when it's completely unnecessary for whatever service is being offered. I think most websites don't need to. And if they're legally obligated in some way, that needs fixing.
...Am I making any sense? I'm having a moment of struggling to render my thoughts to words.