As has been said everyone's requirements are different. I'm currently using an Osprey Stratos with an ICU. My previous experience with specialist camera bags is they over protect with padding, dividers etc and this eats into space if you want to carry non photo items. Alternatively you end up with a larger and heavier bag to fit everything in.
Will my bag work for everyone? Of course not. You can't access via the back and it's not the quickest to get to your gear. However this is compensated by the trampoline mesh panel, which keeps the bag off your back and allows air flow in hot weather. Together with a good harness and waist belt that makes it feel lighter to carry over a distance. It also has the ability to carry non photo gear in a relatively small bag.
My recommendation is to consider using a hiking bag with an ICU if your priorities rest more on the carrying side rather than quick access