So true my friend. Speaking of chapters, I haven't yet made it through Toole's book (I'm getting there), but that's definitely a piece of literature that helps tell the "measurements story."
I completely agree that in theory they "should" sound good if they measure well. I wish I could say this was my experience, but it isn't, though in only a few instances. In my experience, once a few important attributes are achieved (on and off-axis FR, power handling, linearity, etc) the drivers, crossover and build quality become more influential. Many of us know how well the Infinite Primus 360 measured, but I didn't much care for the timbre accuracy/tone of that speaker. It represents a standard for value in loud speakers, but I'd never buy it because it doesn't suit my tastes.
I don't really have anything negative to say about the Aperion's other than the "slow and fat" bass and lack of resolution and timbre in some areas. Microdetails could be improved too, but now I'm just nitpicking.
So you ask what is the main problem with the Aperion's? Well, they aren't better than my Salk's. If they were, I'd own them.
Although, now comparing measurements in-room it seems the Salk's exhibited the traditional smiley face FR in said room, while the Aperion's were flatter through the midrange. Did Tom's room or placement change between these reviews? Just curious.