What you're saying, is like stating, that C-major and A-minor is the same. Sure, their scales do consist of the same notes, but they're different. Or an other example - F#-major and Gb-major. They're also not the same, and this is really important consideration in practice as well, not just a theoretical debate.
Apart from the fact, that what OP suggests is wrong, I do agree, that it would be nice if all scales would be user-definable as well.