I think that
Amaya is one of the most beautiful names I have ever come across, and though I am entirely against changing a name simply for the sake of it looking differnt when spelled (especially if it is adding a lot of "trendy" letters, such as
Emily to Emaleigh), as long as you don't stray to far from
Amaia (which isn't too bad, I actually prefer the name
Maia to
Maya). However, I do like
Amaya better . . . but probably just because I biased towards the one I'm used to.
I would like to add my blanket disclaimer at this time: I am personally against giving Japanese, or any other blatantly ethinic name, to a child who is not of that ethnicity except under certain circumstances (such as a child having enough blood to be considered ethnic {which is completely subjective} but being named for an ethnic relative, or a family living in that country for long term).