The new starwars arena has a shop -- put in X of common and get a random uncommon -- put in X amount of uncommon - get rare, etc.
TBH, I'd rather the option to just buy the White, Green, or Blue gear I need rather then gambling for it for a week. But if all we can get is Random-junk-to-better-random-junk slot machine, I'm all for it.
IF any dev actually liked this, check out the Borderlands: pre-sequel -- The Grinder. It was pretty random but they did it right and, more or less, you could get what you needed (even if that meant thowing crystals into the girinder!)
