Strong blue, depending on what you mean by 'strong' as it is very subjective, is not correct. The blue hue is usually not in your face so to speak, but more noticeable under certain light conditions than under others, especially florescent.
I've said it before, and I will say it again, though... The color of the AR is less interesting than the performance of the coating. Professional AR - that used by my coater, and used on gen watches - does vary from run to run and from watch to watch. The way to judge a coating, therefore, is not by its color but by how well it inhibits reflections. The performance of a quality AR coating in inhibiting reflections on the crystal is FAR more noticeable than the shade of blue or purple.