Later, yes, Riker abandoned his hard line view at the beginning of the book and I am very grateful for that. My point was I am amazed that he voiced this strong hard-line opinion first, not that he went away from it later in the story.
I understand your opinion that you don`t like “post-game wrap ups”. But if you don`t, you need to make sure that your readers – and also less experienced SF readers – are not left hanging and wondering at the end. I am not a fan of hardcore SF. I never heard the word “tesseract” before and when I looked into my dictionary (English is not my native language) I couldn`t find it. I think it is a bit harsh to say (kind of) that adult books shouldn`t have a final clarification at the end. What does that say of readers like me who didn`t “get” it, then?
I like the idea of annotations and I am sure people who read them will find them helpful. Nevertheless, as people tend to remind us, the vast majority of book readers don`t read book discussions like this one and related websites. I don`t think giving your readers a little helping hand at the end of the book so that they can enjoy your novel better and make sure they understand what is going on is not making a book less “adult”. Also adults keep learning, not just children.