Muh I believe the "abuse" farming in general is related how much "coins/h" ppls can do, and that have many factors, like map acessibility (how fast is to acess the map), alt character (how viable it is to farm with alts), coins per mob, mob density, etc. In comparison, bio3 rn is like 4 coins per 12 kills, while power plant is like 12 coins per 240 kills (similar density and map acess), wich take a considerably higer amount of time compared to bio3 to farm same amount of coins, so overral this update was mostly a pure nerf on eden coin farming, bio3 still seems best place to farm, while other still take a considerable more time and kills to farm same amount of coins.
Its impossible to have a "perfect balance" on farmed coins, there always gonna be a best map, but the atractiveness of other maps and farm conditions could be the diferential, like ppls who prefer farm solo, with alts, on maps with good loot table or main office quests, etc., so for that, have a more even "coins/h" on quests of the same tier (expecially the 130190 ones) could lead peoples to consider more other maps.
I think for now, have a better approch on "coins per mob" than "coins per quest", and take in consideration the amount of time it takes to take the quest, complete it and turn in are the most relevant things to consider XD