He has made that conversion to great effect. Forget the sideshows involving his manager, annual deals and boxing matches; Williams has shown plenty of chutzpah in his work.
He's dragged crowds through the turnstiles or into their lounges to watch him on television as he's delivered a new way of playing.
Williams' 1.91m, 108kg frame brought a new dimension to five-eighths play and demanded so much more from defenders to stop his range of offloads.
It shocked if Williams passed in the traditional mode; you blinked and wondered if you were seeing things.
His reverse flick passes, round-the-corner pops or slam dunks were magic. Sometimes they went wrong, badly wrong like one when he strode through the Blues defence and offloaded to thin air.
But when he got those legs churning and moved towards defenders you shifted in your seat wondering how he would react, whether he would accept the hit-and-recycle possession in the traditional way or unload one of his special passes.
In tests, Williams was a little more circumspect; in Super 15 games he increased his expressive outlets.
Of course, he made errors of judgement, such as his blinkered last-minute individual sortie against the Crusaders. But think of another player who would have beaten all those defenders earlier, when SBW charged, fended, danced and pirouetted past a posse of them before he plonked the pill across the chalk. No one. That's what you get with SBW, a bit of exasperation but also stacks of wonder and amazement.
His mitts are like baseball gloves which allow him to hold the ball in contact and mesmerise defenders as he looks for support.
His game improves all the time. He has added pieces like a grubber kick, he has felt the pulse of rugby, learned its cadence and adjusted his lines and angles to count.
When Williams hove into view or had to attend to media duties, he always presented himself well. He answered questions and did his bit.
His game was on the rise, he looked more comfortable with each outing. With Ma'a Nonu in need of rest, Williams produced strong form in all three tests against Ireland.
His legacy will be mixed because he has only dipped his toes into the test waters. But to these eyes he was rugby value and if he chooses to play elsewhere, that's life.
That is a professional player's decision, he offers his CV and employers make their choice. Sayonara, bro.
