I agree to a certain extent that leaving the decision up to a bunch of randomers especially in such a high profile case can be a lottery but to quote the film 'Runaway Jury'... "The jury system was created so that a judge couldn't hang some kid just because he didn't like the look of him"
Convincing a bunch of people as opposed to one person is much harder. Plus the prosecution and defence can tailor their arguments to fit with the judges personal background, one that they will know very well compared to an anonymous jury.
Fair point, but that's why there are 2 assessors to assist the judge. They can actually override her on points of law.