Rucksack vs Sturdy Backpack?

With the heavy ruck packs, i found they make em extremely thick right here. Ah, and it really pinches on a lot of people. Whereas with mos back packs, it's a little bit thinner. So you can adjust it in and out a little bit. And i know that doesn't sound very tough guy, but it's a pain. I have yet to find a ruck sack, a ruck jacket that doesn't have that i don't have to put an assdrisk on when i recommend it.