It's not out of line, but (given my computer illiteracy) you're out of luck in my case.
My Exos 58 forms a nicely rectangular shape when fully packed with the gear I'd carry for a four-night cold weather trip. My summer load, despite tightening the various straps, tends to assume a rucksack (pearish) shape. So, I just ordered an Exos 46 to use for smaller loads.
In the 56, I use the two outside vertical pockets to hold my tent and poles; this means the tent can be unpacked (and repacked) without having to open my main pack in the rain. My water bottle and water filter go in the side pockets; map, snacks, and small first aid kit go in the lid pocket (which can be removed; I've never done it.) That only leaves kitchen, rain gear, food, spare clothes (a pair of socks in summer; down jacket and down pants, and long johns if I'm not wearing them, in winter), sleeping bag, and sleeping pad to store inside. In summer, I stuff my bag into the pack very loosely, to fill up the lower pack and hold heavier items a little higher; they usually end up compressing the bag and gradually working their way to the bottom, creating the rucksack effect.
Hope this helps a little.