Generally-speaking, I LOVE, LOVE this add-on. Here are some issues I'm having, with the ones I think are most important and/or feasible first and moving to things I think are less important and/or harder to implement. If there's a way to do these things that I haven't found, someone pls respond and let me know how. If not, pls consider adding them to the next update.
1. I cannot figure out how to reassign an item to a default category that has nothing else in it. Let me give you an example. I had one item in the default "Miscellaneous" category and I accidentally moved it to another category. When I did so, Miscellaneous disappeared from my bag so I could not drag and drop it back into that category. All of my user-created filters appear in the options menu (and I can drag items into there) whether they are in my bag at that moment or not, but the default filters do not. This is my biggest frustration. Having a section in options to drag items into the default categories would solve this, as would suggestion 4. below.
2. Pls consider having an option to propagate a change throughout all current profiles. I started with a basic profile, which I altered to fit my diff toons professions and needs, but if, for instance, I pick up an item I didn't initially have or want to switch something around, I'd like to be able to change the filter for that item for all my profiles.
3. Pls consider having a small portion of the bag or one filter which contains items you DO NOT want to move around when filters reorganize themselves, for instance healing potions that you might have to get at quickly.
4. It would be super nice to be able to click (or key+click or have an edit mode button) an item and select the appropriate filter from a list, in addition to drag and drop. This would fix problem 1. above and could fix 2. as well, if you allowed a player to select from a "set filter for this profile" list or a "set filter for all profiles" list.
5. Pls consider not rearranging the order of categories until the bag is closed and reopened again. I know this is not as simple as it sounds - if a lot is moved, the bag frame may need to temporarily get bigger or the items inside zoomed out to make them all fit, but it would make organizing the bag much easier.
6. Final, (little) bug - with the user-defined filters, when I make a filter that contains lots of items, sometimes there is not a blank space at the end for dragging new items into. Also, sometimes the icons for some items don't appear in the options menu, but if I mouse-over, it has the name of the item, just not the icon. And lastly, sometimes the list of item icons runs overtop of the next filter title. These are all just UI problems, though, bc all the items are still in the appropriate filter, it just looks messy (and is hard to add new items without the blank space).
Okay, sorry this is so long, but the suggestions are things I don't think would be too hard that would make this already excellent add-on even better! Thanks for making/maintaining it!