What are the downsides of electoral balloting?
First of all, of course the ballot is preferred to the bullet.
The ballot however requires a certain type of person to put him- or herself up for candidacy. Such a person is necessarily of a particular psychological profile. That profile is only a small sub-section of the populace. Balloting -- in and of itself -- prevents realization of government 'by' the people.
Furthermore there are the obvious drawbacks: financial wherewithal, rhetorical adroitness, media visage.
Finally, the campaign is a contest. Many are attracted to the blood sport of it. That contest unfortunately drives the candidates to desperate measures -- not only the attack ads that poison civil discourse, but also the unavoidable compulsion to make promises and to take positions whose purpose is merely to win the election.
These reasons lead us to believe that sortitional selection of policy-making bodies will be the equitable, inclusive and wise 'next step for democracy'.