The vast majority of citizens have neither the time nor the inclination to investigate the credentials of a wide range of unknown individual candidates. Meaningful democracy must be based on a choice between political parties. We all know that the electorate votes for political parties rather than local candidates. It might not be what activists (and writers of letters to editors) want. But democracy is all about the electorate getting what they want, not what activists think they ought to want.
However, a choice between a small number of parties, each of which is trying to encompass diverse points of view, it is a recipe for the worst kind of tribalism, based on allegiance to party before principle.
With an electoral process based on truly proportional representation, there would be electoral advantage for the Labour Party to split along old/new lines, and for the Conservative Party to split along pro-/anti- Europe lines. Thus we would expect to see a larger number of less powerful parties, each with a clearly focused and differentiated package based on fundamental values.