I've also got a Gregory Deva 60. As long as you stay somewhere under 30 lbs packweight it should be fine. Once you go above that, it really does not handle the weight well. My biggest issue with the Deva was space capacity. I originally bought it to do a hut-to-hut type of backpacking trip where I didn't have to carry a tent, stove, bear equipment, or water filtration system. It's a great pack for low-volume trips and I absolutely love the way it fits. When I started trying to use it for extended trips with all of the additional equipment, it got really stuffed really fast. At that point I always ended up strapping the tent and other items onto the outside and the whole system started getting really shifty and unwieldy.

I eventually ended up buying an Arc'teryx Bora 75 women's pack (thank god for SteepAndCheap - I got it for $185). This bag has quite a bit more capacity and can handle upwards of 40 lbs with surprising comfort. Granted, the pack itself weighs something like 7.5 lbs. I do try to keep my pack weight down as much as possible. I almost always buy the lightest weight items that I can afford within reason. E.g. minimal titanium cookware, 3/4 length pad, petite-length women's sleeping bag, my two-person tent is 4 lbs total weight, etc.

However, try as I may, my pack weight always creeps up into the 35-40 lb range when I'm doing full backpacking with several days of food. Especially in cooler climate areas where rain gear and a cold-weather sleeping bag is a must, and in bear country when I have to carry a bear can, spray, etc. It just adds up.

As much as the concepts of ultralight backpacking appeal to me, I'm simply not willing to give up certain creature comforts like a tent (vs. a tarp or bivvy) or a stove (vs. eating cold food) or leaving behind what I consider to be critical essentials of safety (at least 1-2 days of extra food, full first aid & emergency kit, extra batteries for my headlight, a folding knife, etc.). So, I've pretty much resigned myself to becoming strong enough to carry more. Upper body and core exercises help a lot, and I always use trekking poles.

One thing that I do is keep a gear spreadsheet and weigh everything in my pack list. This way, when I'm trying to look for things to cut and lighten the pack, I can see how much it's going to save me (or not). I've got certain sub-groups of gear for "cold weather only" or "bear country" that I can easily add/remove from the total when I'm prepping for a trip.