Maybe this is because I'm a fat guy who struggles in the heat, but this doesn't look like a man who is particularly bothered by the heat.
It's not particularly good posture, but to me it looks like either:
1. He's real intent on what the other players are doing, perhaps thinking about leverage or whatever. (optimistic view)
OR
2. He's bored. (pessimistic view).
IMO, "dogging it because of the heat" as a possibility is a distant third.
I'm inclined to go with 1: Look carefully at the eyes. He seems pretty intent on what's happening in front of him. The odd tilt of his body may be incident to him leaning sideways to get a better view. His mouth is closed. He doesn't look like he's panting or otherwise struggling with the heat. He doesn't appear to be particularly sweaty. His hands aren't on his waist. Sure, he's got a roll around his waist, but that's not unusual for linemen after all; and it isn't a Grady Jackson sort of roll.
The "routine has become commonplace" implication definitely bothers me, but the photo to me doesn't match the claim. In fact, may suggest the opposite when it comes to JH's attention.
Of course, I've never been as impressed by McGinn as others (and he himself) seems to be. So that bias may be entering into things.
And do not be conformed to this world, but be transformed by the renewing of your mind, that you may prove what is that good and acceptable and perfect will of God.
Romans 12:2 (NKJV)