Biggest problem I see is when the kids actually start reaching for the ball instead of receiving it. They straighten the glove arm excessively and then have to bring the mitt back to even start the transfer. Looks like they grab at the ball ( a big reason I NEVER tell a catcher to "squeeze the ball",I believe that just promotes the tendency to grab).At that point, everything is out of whack.
Basically I don't ever want to see a mitt go forward
after the catcher sets his target. I also like the throwing hand behind the mitt in a steal situation and to catch the ball slightly in front of the knees, not between the knees to the chest (I see too many kids/pros not blocking very well when they're focused on catching the ball too deep...almost like they get a little passive). Much of the actual transfer I teach is what Catching Coach talks about on his site.
Coaches yell at catchers to "be a wall back there"; I prefer catchers to be aggressive pillows.
I preach being smooth in everything you do as a catcher. Shifting, receiving, transfer and throwing are usually quicker when done smoothly. Of those, how smoothly a catcher actually can receive the ball is the most important. I don't like herky jerky glovework...makes too many good pitches look like mistakes.
I like what you are saying about synching the transfer and footwork alot. Timing is everything. JMHO