Why don't we have progressive drop rates on nodes? Pretty much everyone does the first round of crystal refreshes on a normal basis, but not that many do the second or more because you're asking for more crystals for the same drop rate. That doesn't make since at all and wouldn't even be legal on slots, which this game's economy is basically just gambling. Why don't you fix this and entice people to spend crystals on higher probability nodes that would benefit them more in their search for very specific pieces?
Disclaimer: I know there is the addiction piece of this game, which I get and don't advocate for.
Still waiting on that edit forum profile setting so I can change my name...