A useful tool for changing the closure strap in the Ego and Super Ego bags is a thin strip of stiff plastic, a little longer than the channel and slightly narrower (but wider than the fastening surface below) with a rounded point on one end. Essentially it would be something like a giant collar-stay. This makes it easy to remove the current strap: just slide the plastic strip in, point first, underneath the strap --- it separates the velcro-like connection, then the current strap can just be pulled right out. It also makes it easy to insert the new strap: just lay the new strap on top of the tool and slide the two in together --- the tool prevents the velcro-like stuff from grabbing the strap until you've got it positioned perfectly; then you pull the tool out from underneath and the strap is seated and secure. This simple piece of plastic makes changing the strap take a total of under 12 seconds (timed with my Super Ego, two straps, and a frosting spatula).
You must already be using something like this in the factory for inserting the straps initially. If not, you should be :-) It would be cool to include one with the bag, or else offer it as an accessory.