Packs are as personal as people. Everyone's body shape is different. Everyone's fitness level is different. And everyone's backpacking technique differs.
Fitness: I train with a 40# pack. If you don't, start. This will effect your preferences for wide vs. narrow shoulder/hip belts (and your pack preferences.) If you get out a lot, you won't need a lot. If you get out 3-4 weekends per year, you need much more out of the harness.
Harness: Your shoulder harness and hip belt will pick up the load from your pack, transferring it to your feet. It will do this regardless of how the pack rides on your back. Some people like the weight to ride on their shoulders. Some like the weight to ride on their hips. You need to determine what you like. I do not like stuff on my shoulders because I have damaged vertebrae there. I look for a 30/70 ratio, shoulders/hip. You may prefer a 50/50 ratio. Or, 70/30 ratio. I cannot tell about your preferences on this list. And, your fitness level will directly effect the width and depth of the padding on the harness.
Stiffness: "Load Carrying", "Pack Collapse", "Load Transfer" all generally refer to how stiff the pack will be on your back. No frames, Internal frames, External frames, Hybrid frames, Front Pouches, are all techniques to change where a load sits on your body. Generally, the heavier the load, the stiffer the suspension. For a max load of 30#, you don't need much suspension. An external pad, or a rolled internal pad and/or a couple arrow shafts will work for 30 pounds. But, to be comfortable, you may need more depending on your preferred carry ratio and fitness level for carrying a pack.
Volume: Some prefer large volume packs for tents, extra canisters of fuel, large food supplies (not necessarily calorie dense) spares, first aid kits, etc. Some prefer the bare minimum. For example, a 20oz bottle of WG and a SVEA weigh more than a similar canister set-up, but, it takes up a lot less volume. How do you pack? 10 Pounds of camera gear is a lot of weight. I have a 6oz camera with several batteries and cards that totals about 1# for two weeks of videos and pics. If you need a DSLR with spare batteries and two lenses, padding, stands, etc, it can easily go 20# or more and take up 3000ci. Only you know what you need as far as volume.
As for myself, I can recommend a Mariposa for generally what I *think* you are looking for. At least you can add/remove parts of it to customize it for your trips.