I think it depends on how you use your pack. If I am just transporting gear to a site, then the big bag pack works OK. But if I am working out of the pack, then the "tactical" packs are a better choice for me.
Having the ability to configure the pack for the activities expected is a big advantage. Some days I want my PLB where I can easily access it, some days it stays home.
I don't have to dig through a big pack to find something. I can open a small pocket, get what I need and return it when done. This reduces the risk of dropping something un-noticed or having rain or dust coat everything. .....
Indeed, how you use your pack does matter. However, rather that re-configuring the pack for different activities, I prefer to choose the pack to fit the activity. Being an old fart, I have managed to aquire a quiver of assorted packs over the years. Here are the ones that see the most use these days.
I have a Dana Designs Bridger that I bought sometime in the early '90s. I think it's about 4000 cu inches. It stays packed all the time for SAR callouts, though the contents vary somewhat with the seasons. One decent sized pocket in the top flap, and two very large "scuba tank" external pockets. But still nicely streamlined. It's been used hard, but is built very stout, my old body is wearing out way faster than that pack.
For casual day hiking, I have an REI Lookout that I have used extensively for several years. About 2400 cu inch. Several pockets easily accessable from the outside, yet still a very clean design.
I also have a Mountainsmith Tour lumbar pack that I like. I mostly use it with the twin shoulder straps, which carry much of the weight. I can put a lightweight shell jacket, a couple of energy bars, and a few odds and ends in it, and two water bottles in the side mesh pockets. It works for short hikes and XC ski trips where I don't want nor need to carry much. It is also very comfortable in hot weather. I sometimes fold the waist belt in, replace the twin shoulder straps with a single strap, and use it as a small carry on for flying. I can put my iPad mini, a book, and a few other things in it and it fits easily under the seat. When I reach my destination it becomes a "man purse".
I also have a Marmot Kompressor Plus. Very simple and ultralight, but still has a top pocket, and a pocket on the back. It is 1200 cubic inches but only weighs 12 oz. When I travel on business, I like to take advantage of any opportunities to get in a hike. The Kompressor can lay flat in the bottom of my luggage, taking up negligable room. But it is more than adequate for a day hike. The last time my wife and I flew down to the lower 48 for a familly gathering we used the Kompressor and the Mountainsmith, and snuck away one day to get in a very nice hike.
Note that all of these have at least a couple of readily accessible pockets for stuff I want easy access to. Other stuff goes inside the pack in light weight stuff sacks for organization. The newer
ultralight dry sacks are awesome. They come in a range of sizes, and are totally waterproof, which is nice for my climate and activities. Using this approach I don't have a problem digging through my pack to find what I need.