In any game, after a system is changed due to suggestions there are always people who come out saying the change sucks. As cliche as this is changing the skin crafting to this was a really bad idea.
The reasoning for the change was that it is tedious individually destroying cards and the system generally was confusing. These are not good reasons.
The tiered system meant that higher tiered skins were harder to get and so there was a lot of value attached to them. Because of card rarities, there was always a sense that you picked up something valuable when you pull an epic or legendary.
For some reason developers underestimate what reward value does. They think that because people say they want things to be easier that is what they should do. Arena net made that mistake and they are still paying for it.
You could have just solved the tedious card destruction issue with multi card selection and solved the confusion problem with a tutorial on the crafting page.
There is no value in the new system. Cards and opals were the only rewards. Opals you rarely get and cards are gone. Without any valuable rewards you are going to get a lot more people who just drop the game.
Whats worse is this is a mobile game so there are probably more casuals here than in Lol or Dota 2. Casuals are not heavily invested in ranking up to please their ego. Without anything shiny to wave in their faces they will move on.