I think this is a great question for me as I have hated the last 2 knife rolls I've had. As the number of knives and tools increases so does my annoyance with trying to lug them around.
Some things that I wish could be fixed:
-Knife roll that isn't long enough for my sujihiki with a saya. I end up having to angle it over the other knives for it to squeeze in.
-Utensil holder compartment that isn't a zipper. Currently it's a velcro mesh and it never holds shut, cake testers and saucing spoon are always falling out the compartment
-It might sound weird but a plain, unmarked roll/case would be ideal for me. I hate having a big knife brand logo on my roll because people get nervous or ask why I'm carrying knives around not realizing I'm a chef. This has happened twice on the subway and I've gotten a million double takes. One person even asked me if I was carrying a gun case because of the shape! Something that had a generic name/logo like "Chef Case" or something would be fine so people wouldn't think I'm a crazy person.
-Knife slots that are actually wide enough for knives. My current case is a 8 knife slot but realistically it's more like 5.
-Another problem is people stealing from you at work. Anyone who has worked in a busy place with a million different cooks coming in and out know that knives "disappear" and more often than not they're stolen. If there was something to deter people from stealing from your case like a simple 3 number combination like a suitcase it would help. It would still need to be something easy enough to openly quickly when you need something fast though.
-Something easy to clean. Everyone's case gets crap on it sooner or later or is handled by hands that were on raw calamari 30 secs ago. There were no cleaning instructions on either of my rolls and I put them in the washer machine on gentle setting and it does a number on them. I've used a combination of disinfecting wipes and soapy cloths and dried over the radiator as a better alternative but it's a major PITA.
-Pen slots that don't work without something that has a clip on the cap. For example sharpies have a clip on the cap and can adhere to the pen holder slot but thin pencils (need a pencil sometimes for inventory etc.) and pens without a clip on the cap slide right out of the holder because it's too wide. There's no tension between the pencil and slot. I end up putting these in the utensil holder which in turn still fall out.