I mean, even when reading the skills and applying some basic math comparison between it and the regular prayer book, you can see that they actually really just screwed it up.

They took way too many parallels of the RS3 version of curses in mind, the only difference is that they for some reason opted to keep soul split out. Even though soul split in the context of old school runescape would be complete dogshit. (assuming it can't stack with overheads)

People forget that Blood barrage is soul split, and beyond a few certain bosses and their mobs that you ignore inbetween kc to use for healing, Soul split in itself isn't all that useful.

Again, assuming it can't stack with overheads.

Every damage amp pray is a hard upgrade from the CoX counterparts.

The curses book is supposed to be a hard upgrade to the prayer counterparts because you do need to go through hundreds of hours of questing and skilling to get access to it. But Jagex really needed to cook the book a bit longer with actual PvM experts from both OSRS and RS3 to attain a point of balance.