I went through this same a couple of years ago looking to replace an original design LowePro. Nothing that I looked at was ideal. My dilemma was resolved when my sons gave me a LowePro AW-400. I, like you, wanted a bag that would work all day while based at either my car or trailer, so no over night hard core camping.
This pack has some irritating design flaws. The pockets on inside of the opening flap are too small for most items unlike the original which had a few large pockets. I find the water bladder to be useless and have discarded it & use that pocket for rain gear, gloves, hats, etc and energy bars depending on the season. There are 6 little flap pockets for CF/SD cards, again useless. I use 16g cards and as a landscape photographer I couldn't imagine needing any others . I wish Lowe had spent the time & energy wasted on the design and sewing of these stupid little pockets for something more useful or simply eliminated them and dropped the price of the pack.
I do like the tripod pocket on the back, but don't use the two on the sides. Yes there are 3 tripod pockets so that means that those other 2 spaces can't be use for other functions. Or put zippers and/or velcro at the top and bottom so they cold be used for something else.
As far as accommodating camera body lenses and accessories, The bag is OK, but just OK. There is no space for filters. Does any pack designer understand that these days many lenses use big diameter filters, 72mm-77mm-82mm?
Cleaning stuff, the pockets in the lid are too small for a blower brush. Speaking of the pockets.... the translucent plastic is nearing opaque making it difficult to see what is in the actual pocket and the zipper design restricts access to the pocket.
Regardless of what I see as design short comings for photographic equipment, the pack is comfortable and carries a heavy load. I'm just over 6' and am able to adjust the pack to fit over summer to winter clothing.
FWIW - 5 lenses and a pro body, 3x & 10X ND and pol filers in 3 sizes, medium weight tri-pod, remote, headlamp, gps, blower & cleaning stuff. The camera holds 2 cards so I don't carry any spares. If I did I'd use one of the hard wallet types not the stupid little pockets.
And no one I know or have met on the trail has carried a 15" laptop. A couple have carried an iPad; this option needs a serious rethink.
FINALLY,TO ALL PACK MAKERS: , make it truly modular, inside and out. Quit trying to make a "one-style-fits-all" from landscape to sports to travel.