A bag organizer might distribute weight more evenly, but the bag still might sag if you regularly carry heavier objects such as water bottle, book, folding umbrella, etc. To give you an idea, today in my MM Iside I’m carrying a phone, key case, small wallet that includes a coin purse, lipstick, comb, small hand cream, tissue pack, eyeglasses in hard case, and various bits such as mints, hand sanitizer, a fan, a folding reusable bag, and a pen case, with no sag at all, and room to spare for a shawl. Good luck!
I don't plan to put anything heavy in there unless it's the occasional pocket umbrella.
I think I might park this for the time being as I'm not in a rush and want to be 100% sure when the time comes. I also want to take a break from having a wishlist as I recently ticked quite a few items off my list during Christmas/birthday (early Jan) and don't have anything on my list at the moment.
I'll definitely keep this in mind later in the year.