Cops, docs and lawyers had to make room last year for some unusual competition. How about a college student/double agent with the responsibility of keeping the world safe? Or a president, afflicted with multiple sclerosis, running for re-election? Or a family of morticians? A new wave of innovative showrunners is pushing the content envelope and taking the genre to places it hasn’t been before — and audiences are riveted. What’s more, this next generation of drama, both on cable and broadcast, is changing the way networks do business.