Now that we are in the Gnome Event who thinks we should go back to the way the drop rate and reward were both structured for the Gnomes initially?
Basically that Gnomes were a rare thing with BIG rewards.
As it stands now For 28 days a month they are ‘common’ with some trivial trash to keep the economy in check.
I got 28 vault keys in 2 days, 80 gem keys, 50 event keys, around 300k gold, 3x sparklesack, 2x common gnome and 1 valraven. 3 orbs of chaos and some traitstones, souls and gems.
It was definitely worth it for me 
Restoring the drop rates to the original would break the economy though, I farmed for 2 hours before the first nerf and made about 500k
I think a reasonable middle ground is to change the drop tables of gnomes that appear in the Vault. I think, but have no evidence to support, that Vault Keys appear at nearly the same rate pre- and post-“nerf”. So the Vault rewards could appear at the same rate as originally without doing too much damage to the economy.
I have found one… wait… two vault keys outside of the one dropped for Raid reward.
I am not impressed with ROI for Vault Keys. They are still FAR to rare for the rewards being offered. Either up the drop rate of Vault keys or buff rewards in Vault battles.