They are indeed not debates in the truest sense; however, Trump used them in 2016 to destroy his opponents.
I would suggest getting the right moderators is far more important than how the debate is structured.
Three things have changed since then. First, those opponents have never recovered. Second, the media shows nothing but contempt for Trump (and MAGA). and Third, Trump is a former president, currently leading the pack by a large margin. He has nothing to gain and everything to lose.