Is it the center panel that makes it hard[er]? If so, maybe turn that into an option... I've got a range bag that has loop on two opposite inside walls, and a piece of fabric with hook on the ends - In this way the center divider can be placed anywhere along the length of the range bag.
Or - another option I just thought about - how about having the magazine dividers be a drop-in assembly? If you turn the dividers into an open-ended box with the dividers fixed in place, you could make it an optional item (with it's own price and then maybe a combo price for the dividers and pouch set) that would drop the price of the pouch itself. Put loop on the inside of the pouch and hook on the outside of the divider box (or vice-versa) and it might be just as easy to convert it as the original, albeit with an extra loose part (that can be folded up and/or folded flat). This way you have a drum-only pouch for those who want that, that can also be used as a basic catch-all/medkit/stripper clip pouch.
Or, combine the two - instead of a pre-made drop-in divider (like the second idea), just make divider walls (aka the first idea). It almost looks like the center and side dividers are the same approximate length, so 1 pouch + 3 separate dividers = Bob's yer uncle. I'd say keep the hard front panel, though - I hate a pouch that doesn't keep its shape.
