Good response! I could add and explain mine in such detail but Im a tad too drunk! Let me try anway
I think for me the biggest ones are tracking the puck, following streakers, movement on transition shots, rebounds on clean shots, vision in general, positioning on screens (lucky 6'3 sob gets to go butterfly and stop most of it) I don't even much care for mobility imo, J.S Giguere wasn't the most mobile during his amazing run, just a brick wall lol... K drunk thinking is hard, but all in all it ends up in the eye test, which is why I think everything from NHL players, to people who watch the game have a hard time understanding all the nuances, just cause a goalie let in 4, doesn't mean he had a bad game.
I think the problem lays with people thinking goalies can 'react' to an NHL lvl calibre shot. Reaction plays a very small part in goaltending. Things move far too fast at that kind of level. I should clarify that one of course does 'react', but you do it beforehand, not after.
I think that E=CH guy was right earlier going by your criteria. His rebound control, side to side, and all that jazz has always been a technical marvel to other goalies but it was still 'raw' in the sense that he wasn't either fully emotionally in it, or would commit too much due to inexperience. Watching him now, he looks to be 'tuning in', and I think we've yet to see him at his best.
Anywho, hope that made sense. Go Canada Go