"But like so many policy changes, it's the unexpected outcomes that need to be watched. One of those outcomes has been a significant shift in the accountability of members."
Dr Smith said list MPs were obviously accountable to their party hierarchies, to whom they owed their place on the list. "But the pervasive power of the party vote has meant all members are now totally accountable to their parties. This House, in so many ways, has become a place of political parties rather than a House of Representatives."
He said he was not calling for MMP to be overturned, but did believe it needed to be re-examined.
Dr Smith also provided a lesson to MPs currently battling to decide whether to support the same-sex marriage bill, saying his biggest regret was voting against the Homosexual Law Reform Bill in 1986.
"I faced the classic dilemma of voting according to my own judgment or the opinion of those I was elected to represent. As a new member, I opted for the latter and I've always regretted it."
Dr Smith also took time to reflect on his own record as a minister in the 1990s - including the controversial changes he made as Education Minister.
Those included introducing the student loans scheme and means-testing student allowances - measures that resulted in student protests.
Dr Smith said he believed the student loans policy was good policy and had made university an option for more people, but means-testing student allowances was unfair, in particular to students whose parents were unable to "camouflage" their income.
He ended by promising to spend more time with his wife, Alexandra, whom he married in 2009, and paying tribute to his long-serving assistant Beryl Bright.