Cohen did a workmanlike job, but 'Jeopardy!' should have postponed the Tournament of Champions until the show's eventual new permanent host is in place.In the middle of a season in which the show looks to replace its late legendary host Alex Trebek, “Jeopardy!” began its Tournament of Champions last Monday. In it, 15 top winners from the last year’s worth of episodes compete for a $250,000 prize. Brayden Smith, one of the last multi-day champions under the Trebek regime, died earlier this year before the tournament’s taping; Cohen honored his life during Friday’s episode.Guest hosting this year’s tournament: Buzzy Cohen,...