I personally think the atma grind was fine how it is probably one of the few. Zodiac weapons are not the best in the game - Lev weapon with mirror is on par with animus(for people who want to grind a different way for a top tier weapon) turn 5 weapons are better than zenith and turn 9 aka 2nd coil turn 4 weapons is better than animus.

Not everyone has to upgrade there relic if they don't want to it was made to be another alternative which they upgrade as content goes along but they didn't want everyone to be running around with the same weapon so they opened up different ways to get top tier weapons and making animus a grind.