In addition to an imaging camera, a radiometer would take the first direct measurements of how much sunlight is reflected and emitted from the whole Earth (albedo). This data could constitute a barometer for the process of global warming. The scientific goals expanded to measure the amount of solar energy reaching Earth, cloud patterns, weather systems, monitor the health of Earth's vegetation, and track the amount of UV light reaching the surface through the ozone layer.
While NASA's Inspector General questioned the cost/benefit ratio of the project (quite rightly -- that's his job) the National Academy of Science, queried by Congress, found the mission to be "strong and scientifically vital."
Nevertheless, the satellite was mothballed for eight years under the Bush administration, and remains in limbo today.
The information the satellite would provide is phenomenally important, and should be important to "skeptics," as well. Directly measuring the Earth's radiation budget (energy in versus energy out) gives you a direct, observed value of global warming, magnitude and sign. By tracking our albedo, vegetation, and cloud patterns, the satellite would monitor three of the most important feedbacks in climate change.
If you want an easy way to tell who not to trust in a scientific debate, it's the side that's afraid of better measurements. Those that want to softpedal global warming or deny it entirely always claim frustration with the lack of clarity (as they see it) in the science, but where's their drive to collect observations and achieve a better understanding? DSCOVR waits in a warehouse, but climate change isn't waiting.