Only place I've found with ridiculous mastery book drops is skeles. The other leafre monsters in the area with the red background drop books at a low rate or maybe it's just specific mastery books. I also think something needs to be done about genesis 20, it is just too rare. We've been on multiple runs now with not a single genesis 20 and the amount of people who need it is super high. Other than that ~npc sounds great.
I think if you introduced an ~npc command, then honestly, we'd be fine with the droprates back at 5x. Potato makes some really good points: I'm not seeing much difference in the FM, nor was I expecting to. The FM is still largely gacha-dominated. This is the one point where Potato and I differ - and that's purely because I'm a lot lower level and haven't yet encountered the mobs in Leafre/Ludi with low drop-rates. I suspect that I'd be heartily agreeing with Potato if I was grinding at Skeles. My inventory stuffing up really rapidly with equips was the one reservation I had about the 5x drop rate, especially since the increase in the spawn rate. Having an ~npc command would solve that problem really nicely. Yes, I'd agree with that. For me, the stuff I keep files under: "godly"; above average; better than what I'm currently wearing; capes; earrings; scrolls. I haven't noticed map lag to be a problem either. Any lag I do get tends to be fairly rare and of the "sudden lag spike out of nowhere" variety that can just as easily happen in an empty town.