Needed an origin episode
Perhaps the most interesting story in the Blackstar universe is the one that the series never told -- i.e., the background.
1. Who is the Overlord, how did he come to rule this planet?
2. What exactly is the PowerStar? Where did it come from? How did the Overlord get it? And most of all, HOW was it originally broken? And how did Blackstar get the StarSword half?
3. How did Blackstar feel, discovering that he was trapped in this world?
A pilot episode that addressed these things would have been incredibly interesting. It's a shame that the show never filmed such a thing. It would have been an excellent bookend with "Shipwrecked," which would be the finale.
By the way, as an aside, in the DVD, Lou Scheimer repeatedly laments that the show didn't give Blackstar super-powers, and calls this a flaw of the series. I strongly disagree. I think it was the strength of the series, that he was human, but with a powerful sword (which doubled as a de facto magic wand).