YABVVU
I am a Sian. There, now you all know, SIAN
It bears utterly no relation the the phonetic way it sounds. If I lived in Wales (where all of my family are) I would have absolutely no problems whatsoever; but I don't and I never have (lived there that is)
I get called Sharon, Shane, Siobhan, Stan and on one memorable occasion, Larne. My nickname at work is Shazza-Rhubarb.
I wouldn't change it for the world. I love, love, love my name - I love it for the way that I was the only Sian (can't do the accent on here, but believe me, it is sexy) in School, brownies, youth club, work place, ante-natal club, workplace. I love the way that it almost always triggers a conversation...even if it's the same old:
"SHARNE? Is that Irish? How do you spell that? S-A-I-N? no? oh"
I love the way it connects me to my Welsh roots; I love the sound of it, I love my name.
I am very lucky.
Why should we all be named in some homogenous English way? Please OP, have a think about your favourite names and I will BET that they are a bastardised form of something far more exotic.