Is stuff hard to get in and out because of the zipper or because the leather is so stiff.
That's a nice feature of my Whitten; the leather used on the pockets is nice and soft. Easy to deal with.
On any type of case with a box pocket - that is a pocket with square corners and only a single zipper on the long side access the interior - the pockets will be difficult to use.
It has nothing to do with the leather. Access to the inside of the pocket is only as good as the method that the case maker builds into the pocket.
On a Whitten to use your example the zipper extends from the top corner down below the lower corner, even a bit too much if you ask me because the zipper can be unzipped enough to spill all the contents of the pocket. It does however provide great access to the contents.
On the Instroke case Cowboy models I put a zipper in the center of the lower pocket and a flap plus a side zipper on the upper pocket.
On JB Cases I do everything from having U-zippers which start on one side at the bottom and go all the way around the pocket to the bottom of the other side, L-zippers which start at the top corner and go down to the bottom corner, I-zippers which are one straight zipper on the side or top, diagonal zippers, zippers which make the pocket open like the hood of a car, etc........ Basically anything anyone wants.
The thing is that a lot of folks sacrifice convenience for looks. At some point Jack Justis decided that his pockets were only going to have zippers on the side presumably to preserve the clean look of the box pocket. And since it's apparent that many people like this "look" they have to sacrifice usability to have that look. The J.Flowers line that we make has adopted, for now, the same style of pockets to achieve the same look. Thus the trade off, clean lines with 90 degree corners vs. easy access to the pockets.
I have invented a box pocket with an L-zipper. It requires a little more refinement before I will use it regularly. When it's done however then it will become standard on all cases which have boxy type pockets. I too dislike owning a case which restricts my access to the pockets.
I feel that one should be able to open and see inside the pocket and find and get to everything that one is looking for.
Pockets are something that I have worked on for a while. I have done prototypes of reconfigurable pockets with dividers like camera cases, have done pockets with compartments, pockets with multiple zippers.
Murnak does some interesting pockets with multi-compartments.
My very first case ever had a "pocket" that was a men's bag (man purse) from the local Walgreens that I glued onto the body of the case. It was actually the best and most useful pocket on a cue case ever.
Right now I just did a protoype of a butterfly case with three-level pockets and many compartments.
Personally I feel that it's to each his own. There is no perfect solution. I like to carry a laptop backpack filled with all sorts of "stuff" that I think I might need sometime. Some of my friends are happy to carry only a neoprene sleeve with a handle.
My "big" case is a Sterling Wave 3x6 with the pockets filled with tips, tip tools, powder, towel, business cards, a survival kit
Right now I am on vacation and the case I brought with me is a GTF 2x4 Storage case with no pockets and no strap. I love the simplicity of it, just my cues and me, I even have to depend on foraging chalk wherever I go.