Despite the regatta being billed as a mini America's Cup rematch, Oracle skipper Jimmy Spithill will not be among the 150-strong fleet as he is recovering from elbow surgery.
But Spithill's younger brother, Tom, will try his luck in this fast-paced, high-level foiling class.
Slingsby, who is rated Oracle's brightest young talent, believes Burling is shaping up as the biggest threat for the world title.
"Peter Burling is the man to beat. I've been watching him, he's sailing really well and improving all the time," Slingsby told the host website for the championship.
"Realistically, there are 10 to 15 people who could win the worlds. People are coming up with new twists all the time."
Ashby, Team New Zealand's wing trimmer for the 34th America's Cup, has described the event as the "single most high-performance regatta I've ever done".
This is a claim you are inclined to pay attention to, given it's coming from a man who has won 15 world championships across three multihull classes.
"There'll be at least eight Olympic medallists, three Moth world champions and 15 America's Cup sailors," added the Australian, who has spent plenty of time in Sorrento in the build-up practising with the Emirates Team NZ crew.