If the inferred purpose of the debate is to assist the electorate in how they should use their vote, then going by the experience of the debate at the last election, it is unlikely to be helpful.
Many of the electorate who voted for Nick Clegg, the acclaimed winner of the debate, felt badly let down by his subsequent performance in government and have since made their views clear in that regard.
Mr Clegg, the debate winner, is now bottom of the poll in the leadership race. What does that tell you? Perhaps that this format favours style over substance.