I like this change. Honestly.
In my opinion, there is no reason to call a weapons skin something like unique or mythic if you only need to open like 15 boxes to find it, while being able to create new boxes out of nothing.
And you are still able to buy it, so where is the problem? Just save some money if you want that special weapons skin so bad!
You should try out farming items in some older games.
Like Diablo 2 LOD for example.
There you have statistical chances of 1 in several millions to find certain items that you even need for certain character builds.

