The former Roosters fullback and coach said Beetson was always given an array of options when he ran the football, and he believes Williams' talents deserve the same treatment.
"He needs more runners, he's only ever got the one option,'' Fairfax said.
"With Beetson you never only gave him one option. You let the man do his stuff and he might slip the quick one or get held up and push away from a few people and get that one a few seconds later.
"There's not enough runners from the Roosters players.
"They've only scratched the surface in terms of his value to the Roosters. I wouldn't be surprised to see more come from him on the weekend.
"I'm sure the coach would be working on that.
"(Trent Robinson) is a good coach and he'd realise there's a bit more to come from Sonny Bill.''
Given many are tipping this could be Williams' farewell to the NRL before a move back to rugby union and the All Blacks, there's no doubt the Roosters will want to maximise every match-winning quality they can from their marquee man on grand final day.
Fairfax was a Wallabies international before he made it big in rugby league and understands the lures drawing Williams back to the 15-a-side game.
He hopes the Roosters hold on to the powerful second rower, but believes the prospect of playing in the 2015 World Cup and potentially the 2016 Rio Olympic Games for New Zealand will prove too tempting.
However, in a short space of time, Fairfax says Williams has made an impact on the Roosters not too dissimilar to rugby league immortal Beetson.
"They both bring something to this side that's invaluable and that lifts teams. They're inspirational,'' Fairfax said.
"He's nothing like Artie ... he's the ultimate athlete Sonny Bill - the physique, the training methods and all that.
"Artie was a bit more on the heavy side, not quite as quick and he had plenty of late nights ... but he still had incredible talent.''
-AAP
