Wow. Great discussion and I missed it. My son's sometimes catching instructor has always emphasized the need for a catcher to be an onfield leader and pitching instructor (getting the best out of your pitcher). Next is the ability to receive well, not give away strikes, and get marginal pitches called strikes by sticking pitches, etc. Followed by blocking or picking (situational and locational-dependent) EVERYTHING. Last was throw-downs given their relative rarity and given the pitcher is making it mathematically impossible to throw many runners out short of an absolute cannon.And velocity means nothing if the accuracy is not there.
However, I'm coming to the opinion that throw-downs and pop-times, as a measureable metric, get the lions share of (disproportianate) attention at high-level travel levels and beyong. That's how it is so that is where he is now putting much of his focus and work...in addition to hitting (he bats lefty), which has always been hugely important to him.