The lid just does not fit very well on all Ospreys, it's too small, too shallow and the attachment points are marginal. Yes, I typically leave the top lid home anyway for weight savings. I would love to see an extension collar instead, however.
The Exos series actually has usable axe loops, the top attachment does exist. The Aether series is just plain missing the top clip for axe, so as soon as you open the lid the axe falls out. Seriously? One is supposed to use one of the side straps or the lid to hold the axe? I am pretty sure the designers sort of saw axe loops somewhere, but did not actually know what these are for. Cargo cult style.
I would rather have less silly stuff on ultralight Ospreys (the poles attachment that does not work all that well, the little camera pocket on shoulder strap, the sleeping pad loops). But I understand, they would not be able to sell them otherwise. And if you don't like it, just take a hot knife and cut it off.
Oh, another complaint I have for Exos 58 is its shape. It's too wide and too deep (places weight too far from my back), so it turns into a watermelon shape every time I pack it. I would rather see a narrower and taller main compartment. Again, an extension collar would be nice. Looks like a pack from 1950-ies :)
Still, all that said, Ospreys are so comfortable for me, I forgive all their issues.