A LOT of the old EU had writers who had NO CLUE what to do with Luke, and had absolutely terrible characterization for him. I have a hard time with Luke in most of the old EU outside of Zahn. Shadows of Mindor is one of the only exceptions.
You have to remember SotME was written less than a year after the release of the first film. So the fact that Foster is trying to hook up Luke and Leia... wasn't a weird concept at that point. Other than that one issue, it's an enjoyable romp.
Pro-tip: my favorite is Shadows of Mindor