Let's look at the success rate (no cowls unlatched in-flight) between the various airlines operating this type design (multiple aircraft types?) since the latest SB was issued.
Now if this was so difficult to comply with I'm quite sure all the airlines would be proposing their own work-around to Airbus without any help from this forum.
The question is did they?
or did they just accept that the devil they know is better than a new Airbus invention?
If the last statement is true then the issue lies more with the operator than the engineering folk at Airbus especially if the operator convinced their regulator that they could/would easily comply with the Service bulletin.
Now I don't know the answers to the questions I raise but I certainly don't trust the viability of the solutions I've seen posted on this thread.