Home and Away actor Jacobz, who is also the presenter of the Australian version of the reality show, said that Keating and fellow judges Guy Sebastian and Mel B all want to fill the shoes of former 'Mr Nasty' judge Kyle Sandilands.
Jacobz told the Herald Sun: "Because we don't have the mean guy Kyle, the guys have turned a bit mean. They are not relying on Kyle to say the mean stuff and are not scared to tell contestants what they really think. There have been plenty of tears."
He also revealed that Mel B has proved the "hardest to impress" of the judges, but added: "When she gives a thumbs up, she means it."
Mel B and Natalie Bassingthwaighte were introduced to The X Factor this year after Sandilands and Natalie Imbruglia quit the show. Sandilands said that the job involved too much "work".
Earlier this year, Keating admitted that he was scared last year's winner Altiyan Childs was turning into a "train wreck" after he got caught up in a drugs scandal and got engaged to a teenage fan.
Childs has since said that he "trusted the wrong people" after his win and is now getting his career back on track.
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Watch Altiyan Childs perform 'Beautiful Day' on last year's X Factor finale below: