Hold on, what?
In your example do you mean,
- select 15 randomised people to run against each other to win 5 seats.
Or,
- Elect 15 people from a randomised larger pool of people. And those 15 people are then lotteried for each decision/period into the council of five position.
If its the second one, thats interesting as fuck. I think I'd still hold my reservations about ongoing groups leading to factional groupings(essentially a shit form of a Party), but its really a rethink of the system elevating the utility of randomness.