Jury nullification is a bad idea because law should be made under established and visible procedures and in legislatures accountable to the electorate, not ad hoc by micro-legislatures deliberating in secret and accountable to no one. The latter, in slightly different and earlier forms, had a pretty well known name: Vigilantism.
Today, however, I ran across another reason to oppose jury nullification.
A round of applause for Facebook, enabling the removal of a bad juror.
Of course, this is one more thing for trial prosecutors to watch out for, as if they didn't have enough already.