I had the exact same feelings. I took most notice of the salts that added negative things to the water. Some had much more ammonia and phosphates then the rest. I figured that you could make up the things the slat might be missing(mag, cal, alk) with supplements, but dealing with phosphates sucks.
Tailoring salt chose to livestock is interesting. However, all aquatic animals benefit from balanced water chemistry and they all suffer if there is a deficiency in certain elements.
That being said I have 2.5 buckets of regular tropic marin and will probably keep using it.