add some boss spawns like thermonuclear devil bosses, maybe even some wildy bosses, for (5% less drop rate for the safety) maybe KBD, or maybe even an added upgraded elixer pool, that can last twice as long as the normal elixer pool, and that book that does nothing, can spawn "stronger versions" of your slayer task monster (not bosses ofc) but it'd be like the superior versions like on osrs they have a 1/4k chance to drop "superior" items which would be slightly better than chaotics but untradeable (weapons)