I'm reading the annotated version now and there were some interesting tidbits in the margins - the Sherlock part did seem very logical, once said I can't unsee it now.

I wonder if in Rebels Thrawn wasn't so much as not understanding of it to not believing it had as much merit? Dismissing it in part because it lacked cohesive art - or something like that (I just made that last part up as an example of why he'd behave the way he did). It's entirely possible that it was simply required for the plot and Zahn was consulted but I don't think he was overly involved.

I didn't catch on to that take on Karrde before this reading either.