Muh I think the real "abuse" with any of these item reward quests is how using alts exponentially increases the farming speed. Someone dual-clienting will farm coins twice as fast, and someone using max alts will collect them tenfold faster.
This isn't limited to eden quests either, for anything where the quest reward is the main objective, using alts just makes the whole thing too easy. I'd say collecting eden coins was never "too easy" for single clients, even in bio. It was just fine, maybe even a bit too hard considering how many times you have to repeat them for just some consumables. If there was gonna be a rebalancing, I'd prefer it to focus on the multiclienting aspect instead. Although I do appreciate the coin increase for the other maps.
And I'm not even against using alts, I do it too occasionally. I think it's fine for people who do it to farm faster to some degree. But currently it seems a little too much, each alt you add shouldn't just double your farm speed.