Ruiz, who stunned Joshua to take three of the four major heavyweight belts in New York in June, is slated to rematch the Briton in Diriyah on 7 December.
“I think Ruiz would clearly be more comfortable in Mexico, Los Angeles or New York,” said Bunce.
“I don’t think he would have been too uncomfortable in Cardiff. This will be a culture shock for him.
“Joshua spends a lot of time in Dubai, which I know isn’t SAudi Arabia but it is the Middle East.
“It doesn’t mean I think he will win or I’m dismissing experts who think Ruiz has Joshua’s number. I just have a feeling this might just favour Joshua a bit more.”
‘Men and women are welcome’
Ruiz – the IBF, WBA and WBO belt holder – has not spoken publicly since the SAudi rematch was announced on Friday but Joshua’s promoter Eddie Hearn believes the champion is probably angling for more money, and has quashed concerns he has not signed to fight.
Hearn has been forced to field questions on his choice to host an event in a country which Amnesty International says has an “appalling” human rights record.
The 5 Live Boxing podcast has received many emails criticising the move, while social media debate has seen fans confused on how to obtain visas or on whether women can attend the fight.
“The moment you buy a ticket online you will be automatically issued a visa for 30 days to visit and spend time in SAudi Arabia. Everybody is welcome – men, women, everybody.”
Human rights issues in SAudi Arabia
A report by Human Rights Watch in 2018 raised a host of issues in SAudi Arabia, ranging from the arrests of women’s rights activists, to the fact women still formally need permission from a male guardian to travel abroad or obtain a passport.
The report also raises the murder of Saudi journalist and critic Jamal Khashoggi inside SAudi Arabia’s consulate in Istanbul.
The country is, however, trying to transition away from a largely oil-dependent economy.
Women were allowed to drive from early in 2018, while high-profile sporting and music events have been delivered as part of a vision to modernise the country.
Hearn hopes staging the biggest fight of the year there can prove historic for Boxing but with Amnesty International urging Joshua to “speak out” about the human rights issues, the delicate nature of this Middle East move is evident.
BBC Sport Boxing correspondent Mike Costello said: “For Joshua, this does introduce an unnecessary element of pressure as he will have to talk about this at some stage. He will have to say something and that will echo around the world.
“There will be people saying to us ‘why are you endorsing nations like this by covering fights like that?’
“But if we look back through history, if there was one fight you could ever cover I know you’d say ‘The Rumble in the Jungle or the Thrilla in Manila’.
“The Rumble was in Zaire – now the the Democratic Republic of Congo – which was governed by Mobutu Sese Seko, who shortly after he came to power, hanged ministers from the previous government in the stadium where the Rumble in the Jungle took place.
“It sounds like we are making excuses but I think you reach a point where you have to accept you’re a broadcaster covering sport, not a morality correspondent.
“It’s a really difficult one and that doesn’t mean to say I am happy about going to SAudi Arabia. You wrestle with it.”
Bunce added: “I think Joshua will have to be very careful with what he says. He can’t take a passive or dismissive stance.
“I’m delighted the fight is on because I didn’t think it was going to happen.
“I am delighted Joshua will get the chance to get rid of whatever has been on his mind. I am delighted Ruiz will probably make double the money he made in New York, so his and his family’s life will continue to change.
“We do have to be mindful of cheerleading. I am not looking forward to having to defend my decision to support this fight because let’s tell the truth, that’s trickier. You still ask the question of yourself.
“What can vast sporting events do? They draw attention but they also perhaps make the people in places like SAudi Arabia think differently going forward.”
A women’s bout on the cards?
Hearn has said a successful investment and event in the Middle East could change Boxing forever.
He has talked up the “mind-blowing” plans to erect an open-air stadium which will hold more than 12,000 on fight night.
Sky Sports Box Office will cover a main event expected to start around 21:30 GMT in the UK.
Tellingly, however, a US broadcaster has not yet been confirmed as the time zones will be testing for the country’s pay-per-view market given the bout could start around lunchtime on America’s west coast.
When Joshua was beaten by Ruiz in June, the undercard served up a stunning women’s encounter when Katie Taylor controversially beat Belgium’s Delfine Persoon.
The contest drew plAudits for its ferocious nature – but could a women’s bout possibly make the undercard in a country where exercising in public is often seen as taboo for women?
The BBC’s Boxing experts think it’s unlikely.
Costello said: “June in New York was one of the Highlights of my career and the night began with Taylor taking on Persoon in a fight that most people ringside agreed was the best women’s fight we had ever seen. That couldn’t happen in Diriyah.”
Bunce added: “In theory it couldn’t happen. What if there’s a women’s fight on the bill? Don’t rule anything out. Who knows? What a coup that would be.”