Public Acceptability Criterion
The Public Acceptability Criterion is not a true criterion as such, but more of a measure of how easy it will be to get the public to understand and adopt a new voting method.
As suggested by Russ Paielli:
By the way, let me suggest another "criterion" for public acceptability. If voters have an election method carefully explained to them for, say, five or ten minutes, then most of them should be able to accurately paraphrase the rules on the first try. And they should also be able to do it days or weeks later, perhaps with only a brief one-minute refresher.
Not a bad starting point. Anybody care to add more?