If he was being hired as DC there might be some legitimate griping.
But when a former NFL DC is hired to essentially critique the O based from how your opponent's D might see it, key on certain things, and defend it, that's at worst neutral in its effect.
I imagine McVay isn't the only guy to employ such a position. But, just as the Rams were early adopters (even pioneers) of data analytics to evaluate players, so I'd bet just how McVay staffs also has some innovation. Of course, you must have an owner willing to shell out the money to have a larger than typical coaching staff.
