replaced by ex-Ireland international Anthony Foley.
O'Connell, who has been with the province for almost 15 years, helped them to last year's PRO12 play-offs but a 16-15 defeat to Glasgow Warriors ended the title charge.
And the 34-year-old believes Penney's replacement can get them playing a more productive style of rugby this time around.
"I think when you've got to give something a lot of thought - which we did at times under Rob's style of play - you can struggle to be direct and aggressive in doing it," he told the Irish Independent.
"The best coaches I have played under like [Warren] Gatland and Joe Schmidt simplify the game. The easier it is to get into shape and pattern, the easier it is to be effective.
"New Zealand play it. They play it from the age of four and Super XV is set up a bit like that. It is second nature to them and you can see the subtleties.
"At times in the [Penney's] second season we did that, just not consistently."
As for his own personal prospects, O'Connell conceded an ageing body is taking its toll and that appearing at the 2015 World Cup would be an impressive achievement.
"I'd love to go to the next World Cup but I'd like to go there in really good shape as well," he added.
"I certainly do think about retirement but I haven't made any hard and fast decisions. It's just about how my body feels. It feels quite good at the moment."
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