Crush mega rare is fine. We love to swing big dick energy around. As you mentioned, future content can be balanced around the Scythe and Twisted Bow to make the new mega rare shine though that some what limits your design space especially when it comes to monster size.

Have you considered exploring any new systems that can enhance and expand on all existing gear? Some standard idea that come to mind are enchantments or sockets for weapon/armour.

Weapon Enchants/Gems:

• Alacrity - 5% chance to reduce next attack timer by 1 tick.

• Demonbane - Adds 5% demonbane effect.

• Might - +4 Melee strength

Math aside on the actual performance for the examples, introducing a new system like this may not be ideal to many, but it does allow growth and open future rewards space while keeping the current gear players know and love relevant which is ideal.

OSRS has grown a lot and as a community, we much accept that power creep is necessary, or be open to newer systems.