Notes from my experience with this mod so far:
Some stuff from Travelling Merchant needed for some souls is extremely rare, like Companion Cube or Diamond Ring. It makes a big disparancy between some souls that you'd expect to be on the same level. I haven't found Pulse bow for Sharpshooter's Soul in my ≈400 ingame days over 4 playthroughs with this mod.
Gating most souls behind Crucibile of the Cosmos is kind of weird decision - at the moment you get it you have beaten all the content already, so those souls barely have any use. And extreme rarity of some components, as well as necessity to have several worlds to gain them (two at least, with different types of world evil, and I had to go through a dozen worlds to find The Guardian's Gaze painting) discourages from crafting all of them for a new playthrough.
Having to massacre NPCs for their weapons... Not only makes you a terrible person, but also is long and boring. Also, catching NPCs with bug net is a good idea, but when you are catching critters in town you typically end up accidentally catching NPCs, especially with golden bug ne.
Masochist mode heavily relies on wide addition of
ing debuffs everywhere - you either can't properly control your character or the character is simply locked in immobilized state. Inflicting Confused, Dazed, Clipped Wings, Flipped, Cursed, Lethargic, Stoned and other like those on every occasion is not a true challenge. Also, randomly spawning bosses every 30 seconds is quite annoying.
Supersonic Speed being binary is inconvenient - you either move way too fast to have any precision or like without speed accessories. With disabled boosts it should work like Frostspark boots IMO.
Bugs and other oddities:
Eater of Worlds Staff seems to not change damage output with more segments, unlike Stardust Dragon. Together with poor base damage it makes this staff pretty useless even against weakest of enemies.
Crucibile of the Cosmos does not inherit Alchemy Table efficiency.
Copper Lightning causes massive performance issues in dense crowds.
Dark Artist enchantment (and all gear where it is a part) causes damage to exponentially raise infinitely when weapons are used.