Yet the 25-year-old was having the last laugh this weekend after she put paid to theories that she spent more time crashing to the ice than staying upright with her stirring performance to Mozart's Concerto No. 23.
Kostner, who became the first Italian to win the women's world crown, will not have much time to savour the triumph though as Saturday's win would have again raised expectations that she could finally end her Olympic nightmare and win gold at the 2014 Sochi Games.
However, if her dreams are anything to go by, Kostner is unlikely to get much sleep over the next two years.
"When I dream about figure skating, these dreams are never good. Either I am late to the warm up or I have problems with my laces," Kostner told reporters.
The other winners in Nice are already considered as Olympic front runners but they were left cursing a host of silly mistakes that could have easily cost them their titles.
Vancouver champions Tessa Virtue and Scott Moir captured their second ice dance world crown but failed to produce the "fairytale performance" they had hoped for. They described their interpretation of the Audrey Hepburn/Fred Astaire musical 'Funny Face' as a programme littered with "bobbles" and "stumbles".
Aliona Savchenko certainly looked livid as she aimed an imaginary gun at her partner in the kiss-and-cry area after Robin Szolkowy messed up their synchronised spins by starting on the wrong foot and also singled an Axel.
"I was really angry at him for messing up the spin," said Savchenko after the Germans snatched their fourth title by edging out Russians Tatiana Volosozhar and Maxim Trankov by just 0.11 of a point.
But if there was one performance the French crowd felt particularly short changed by, it was Patrick Chan's.
The fans booed, jeered and hissed for more than 10 minutes after the Canadian was declared the winner despite crashing to the ice on a relatively simple double Axel.
If Chan was rattled, he certainly hid it well and passed off the incident as "background noise" that will serve him well in Sochi when the fans will be extremely vocal in their support of the Russians.
"I didn't actually notice the noise. I could just sort of hear it in the background," Chan said after he became the first man since Stephane Lambiel in 2006 to win back-to-back titles.
"I wasn't sure if it was cheers or jeers but either way it was pretty cool.
"The crowd really got into it, which is what I want to see in skating more. Olympics in Sochi will be even crazier so this was good practice."
Turning a deaf ear to such distractions might not be a bad thing but what Chan cannot gloss over is that, despite being undefeated since 2010, he failed to pull off two clean programmes in any of his five international competitions this season.
"Every time I walk on to the ice for a competition, my goal is to do a clean programme and to perform my heart out. I get goosebumps doing the programme every time," Chan told Reuters before the start of the season about his Concierto de Aranjuez free skate.
However, rather than experiencing goosebumps, Chan has had to get used to suffering a multitude of bumps and bruises as witnessed by those in Nice who saw him holding an ice pack to his black-and-blue body following the Axel mishap.
If the trend continues, he might see a new upstart such as 17-year-old Nice bronze medallist Yuzuru Hanyu steal his thunder. Yevgeny Plushenko, the 2006 Turin winner who is recovering from knee surgery, will also be pushing hard to succeed in front of his home fans.
Canada topped the medals table this week with two golds but for nations such as Japan, Russia and the United States, who all won minor medals, the championships showed just how much ground they need to make up if they are to make an impact in Sochi.