Having played it, I say it's pretty interesting. First, you save Copernicus from being killed with a relatively long fight. After saving him, you take on certain missions, which is basically warning his fellow scholars about the plot against them. There are twists to saving them, which makes it less predictable than, say, "warn him, then escort him somewhere safe". The whole DLC isn't "long", but it adds more intrigue to the overall story.