Lennier is hardly objective on the matter of love, unrequited or not. I would hardly call Delenn and Sheridan's love for each other unrequited.
On a different subject, I finished the first Techno-Mage novel, and I would hardly call The Shadow Within
a prequel to it. Yes, the Anna, Kosh, and Morden bits are consistent, but we already know enough about those characters from the show that their minor parts of this story make sense. I liked Casting Shadows
much more than I thought I would. It's kind of like the Young Jedi Knights
series with its coming-of-age-with-strange-powers storyline. Cavelos did a great job making me care about all of these mages that we never saw on screen. I'm curious to see what Galen and Elric do in the next book.