One of the things that I was surprised about was the class not taking concepts from a prestige class, much like the magus did. When I first heard about it, I thought it would be a shoo-in to have hints from the Sleepless Detective, namely the ability Canny Sleuth. I agree with the poison use being out of place and canny sleuth, to me, is a sensible replacement that isn't out of the scope of what is expected by the name of Investigator.
