My honest opinion of Holgate is that he needs a sustained run of games, next to a decent centre half (basically not Michael Keane), as he like Keane, has lapses in concentration, and needs games to build up some rapport and understanding (which when I type it, sounds ridiculous, they train together 5 times a week), but he looks lost in occasions. For me, he needs to show something different to what Keane offers, and he'll have a chance, so I guess my point ties in with your point. He plays well in areas, but his overall game is lacking.
He may get a chance in the coming weeks, with the way our injuries are, we may have to play 5 at the back, just to field a Starting XI.