Yep, it's awesome when someone really gets your fic--and awesome to be told that, too! I know I've been elated as a reviewer when an author told me I totally got it. Yeah, the author is dead (I mean, not this particular author, not literally. I hope) and all that (post?)modern stuff, but it's still nice when you achieve that kind of connection.

The "cool motive, still murder" type discussions IME generally come from perceived differences in emphasis: The author might think the "murder" part is a foregone conclusion and focus more on the cool motive, which the reader might read as deemphasizing the murder bit. Sometimes story is a series of misunderstandings. :)