Actually, I like this idea. If not necessarily code-modifying, at least some type of "hints" that could be provided in order to see potential optimizations. For example, a query which uses an 'orderby' and then performs additional filtering in the pipeline.

Suggesting something like "filtering before ordering optimization" would be very handy. (Now making the actually code change would be superb.) Preferrably this would analyze the optimizations you highlight in your book.