What I've found is there is no barometer that allows you to chart when you're oversaturating a desire. You're left really trying to respond on a gut level, because by the time you might do research, it's already too late. There's also a healthy tension between what are very sound business objectives and a very amorphous desire to preserve what's special.
In order to appeal to a wider audience on network in order to survive, generally your characters need to be, at a base level, a little bit more likable.