packing your neck is probably better than looking up but with that your neck should be packed before you start heading down, its not something to start half way through the lift. i was always told chest up and head up but when someone told me to push my hips through it all got a lot better. and yes my rational is getting stronger leg and core strength, never seemed to hurt any one before.
your back giving out of the bench will totally happen if you kept benching that way. if you can get stable in that position its great for moving max weight but eventually your back won’t take it any more. it might take a little while to get the bottom end strength back up since you’ll have to move the bar further but that just means you’ll get a bigger and more powerful chest
over all not quite as sweet as camo leggings but you have some good lifting going on[/quote]
If he’s using the muscles around his spine correctly and he has no pain in his spine then I wouldn’t see it being a problem. With that being said, that’s the reason why I asked if he uses his glutes properly to create leg drive because using the glutes and abs limit the amount of anterior pelvic tilt, which usually can lead to injury when you couple hyperextension with no muscles absorbing the load.
I would lean towards your opinion that there’s a bit too much hyperextension but I would need the OP to clarify. I used to do the same thing thinking that a super arch was important but it’s more important to get the right muscles involved.