Like every other measure, visionary leadership would be as prevalent in a proportionally representative legislature as it is in the general population. Some may criticize this fact by saying that this is exactly why we force candidates to engage in combative campaigns … so that voters can choose the ‘best’. Unfortunately what is chosen in that case is ‘the most combative’.
But more important than 'visionary leadership' among the legislators themselves is the fact that visionary leadership will be available, as it is now, from outside sources -- from lobbyists, citizens, leaders of all stripes and other petitioners. The actual architects of most laws in current legislatures are rarely the elected congresspersons but instead their staff and their various committees of advisors. The Senators and Reps are simply the deciders who make the choices among all the options presented. Quite rarely is leadership coupled with electability, which is the precise point of sortition -- to remove the influence of money, influence-peddling and power-brokering from the process by which our leaders are selected.