We need Raids 2 to add justi/scythe just for originality. GWD bosses are really easy, there's no sense in giving these better drops when it gets more starter gear in the game.
Adding another point system to make it easy to get high level gear kinda defeats the purpose of the rarity of items.
Guaranteed drops defeats the purpose of having a drop table. Not only that, there's a lot of extra coding involved since I'm sure the guaranteed numbers aren't anywhere in the source.
None of these you listed would really help the eco at all.
The economy is decent despite everything that's in the game. Magic Well is the major problem due to money being constantly pulled in the game from afks/drops/trading/selling store items. There's also the items being removed from the game causing inflation of other items and causing a major fluctuation in the costs of said items and their better parts. But the only way to fix this is to either remove the well, remove afks, or add a gold sync that takes gold out of the game in exchange for something (such as the superior pets). The last option being the best due to the meta of having afks.