No voting system can deal with people who have arbitrary preferences. I've lost track of the first time I looked into this, but I'm pretty sure that if you map preference space, impose a metric, and say that each candidate and voter choose a location in that space and the votes go in proportion to the distance by that metric, it gets around Arrow by imposing the requirement "voters may only express a preference that their representatives share their preferences", which is reasonable but still violates the theorem's preconditions.