I don't see why they didn't make the alex drop rate similar or better than dynamis drop rate considering the alex part of mythics requires 3x as much as the final stage of relics.
In my opinion, they could do two things:
1. Drastically lower the alex part of the mythic weapon, and maybe lower the einherjar and nyzul tokens as well.
2. Drastically increase the drop rate of alex. It should be like dynamis. ALL monsters in the zone have a chance to drop alexandrite. All Archaic machinery also have a low chance to drop cotton coin piches. Cotton coin puches are 100% from NMs, with a low chance to drop a linen coin pouch. And finally 1 linen coin pouch is 100% guarenteed from the boss.
Having a system like number 2 would be far more fair, considering i've seen bastok runs where people have gotten 800+ currency, compared to people barely being able to get 100 alexandrite a run. The arguement of being able to go in salvage everyday, while only being able to do dynamis twice a week will no longer be valid with the coming changes as well.