There are a couple of schools of producer these days. Guys like myself who came up in a time where the producer was able to write, arrange for different instruments, suggest harmonies, hear a song and help determine for and structure and so on.
Then there is the "I have a computer and some software so I'm a producer" type. These producers are more focused on groove production based on loops and samples. I don't dispel this method but I feel to be a great producer you should be able to do as much as possible. The more tools in your toolbox the more you are able to create better music.
That's the musical side of things. A producer also has to submit a budget and stick to it. It is your job to give your client or a label what it's going to cost and a breakdown of what goes where. It is your responsibility to secure musicians for a session, book studio time, hire arrangers, etc. I always like to say the producer is akin to a director in a film.
Having said all this "the producer is not God" You have to be able to freely communicate with an artist or group and be open to ALL idea and suggestions.
Hope this helps.
Cheers,
buzz