A little Molle and a velcro panel won't grab much attention these days as long as it matches the color of the bag. I have an urban grey GR1 and I typically don't have any patches or Molle accessories attached, and when I travel via rail or air, I always sanitize the exterior - no morale patches, flags, carabiners, Molle accessories period.
That is a good looking bag. Question about the sling bags. Wouldn't it be hard to run with in a bolt situation?
I gotta say I'm pretty happy with my new 5.11 AMP 24. When I peel off the patches, it can easily be mistaken for a snowboarder/skateboarder type of bag. Since I got it in their Tungsten color rather than black or tan, it's less likely to draw attention as a tactical bag.