I stopped flying 320 family aeroplanes nine years ago (V2500 and CFM). Back then this was a very well known problem. Obviously it's still ongoing and a better solution needs to be found.
However I was trained to always squat down to visually check the latches and check for a gap. Contrary to what some have written here it's hardly onerous and you don't get your knees dirty (if that's a worry change jobs). I'm sure thousands of 320 drivers do it every day. A nameless BA mate told me that until this incident he never checked the latches - he does now. I suspect the same may be true at other operators.
I'm sorry, but is a decent walk round too much to hope for? Isn't it part of our job to compensate for known issues with the machines we operate (for none are or ever will be perfect).