I rarely play silver challenges, i find most extremely difficult.
They invariably have rules and placements that are outside the norm. As a result, an attempt on puzzles or class challenges means i spend the first run learning or relearning the rules of a challenge. Then subsequent runs i might have a chance.
So getting an item through challenges represents a lot of work for a casual player like me.
I think there's an interesting mix of purpose here. The devs have supplied class challanges as a means of getting items reliably. On the one hand, the challenges must actually be challenging so players,appreciate them. On the other, many players see them as a means to an end, and resent that challenge.
I feel that the class challenges had little net effect on the way players interact with the locker, only provided an alternative means. If anything its reinforced the idea that players should be playing the locker rather than the RNG.
The locker is in a weird middle ground between becoming the whole game and being useless. Personally, i don't use it to its full potential because of the effort involved in lockering items. Its kind of like getting a new bike and only,being allowed to ride it in the backyard, and i think the passion and frustration of players stems from this.
Boundaries are great, but restrictions are not. Does that make sense?